- Add preliminary (yet to be tested) handling of timestamp invalidation
  issues that can happen with specific devices, where timestamps can
  reset or go backward/forward in time with no rhyme or reason.  Spent
  the entire day just trying to figure out the best way to handle this.

  If both audio and video are present, it will increment a reference
  counter if video timestamps invalidate, and decrement the reference
  counter when the audio timestamps invalidate.  When the reference
  counter is not 0, it will not send audio as the audio will have
  invalid timing.  What this does is it ensures audio data will never go
  out of bounds in relation to the video, and waits for both audio and
  video timestamps to "jump" together before resuming audio.

- Moved async video frame timing adjustment code into
  obs_source_getframe instead so it's automatically handled whenever
  called.

- Removed the 'audio wait buffer' as it was an unnecessary complexity
  that could have had problems in the future.  Instead, audio will not
  be added until video starts for sources that have both async
  audio/video.  Audio could have buffered for too long of a time anyway,
  who knows what devices are going to do.

- Fixed a minor conversion warning in audio-io.c

Add copyright and name to files it applies to.

Various changes for wxGTK

Clean up a little bit of code that was unnecessarily nested.  Still a
little squishy but better than it was.

 - In the audio I/O code, if there's a pause in the program or its
   threads (especially the audio thread), it'll cause it to sample too
   much data, and increase line->base_timestamp to a potentially higher
   value than the next audio timestamp that may be added to the line.
   This would cause it to crash originally, because it expects audio
   data that is within the designated buffering limit.

   Because that audio data cannot be filled by that data anyway, just
   ignore the audio data until it goes back to the right timing (which
   it will as long as the code that is using the line accounts for its
   current system time)

 - Often, timestamps will go "back" in time with certain..  terrible
   devices that no one should use.  When this occurs, timing is now
   reset so that the new audio comes in directly after the old audio
   seamlessly.

 - Audio data was just being popped to the "front" of the mix buffer, so
   instead it now properly pops into the correct position in the mix
   buffer (proper mixing still needs to be implemented)

 - Added a test audio sinewave test source that should just play a sine
   wave of the middle C note.  Using unsigned 8 bit mono to test
   ffmpeg's audio resampler, seems to work pretty good.

 - Fixed a boolean trap in threading.h for the event_init function, it
   now uses enum event_type, which can be EVENT_TYPE_MANUAL or
   EVENT_TYPE_AUTO, to specify whether the event is automatically reset
   or not.

 - Changed display names of test sources to something a little less
   vague.

 - Removed te whole "if timestamp is 0 just use current system time"
   when outputting source audio, if you want to use system time you
   should just use system time yourself.  Using 0 as some sort of
   "indicator" like that just makes things confusing, and prevents you
   from legitimately using 0 as a timestamp for your audio data.

 - Circular buffer code wasn't correctly handling the splitting of
   newly placed data segments, the code was untested and turned out to
   just be backwards.  It now copied the data to the back and front of
   the buffer properly.

For one, I added a new member gs_window for future use.
The member is "display" which represents our connection to X11.
Ideally, we should use this specific connection to deal with our Window.
For now, it's disabled. Read comment for more information.

Secondly, wxGTK apparently doesn't map our window in some cases.
This causes the window ID passed to be bad and will stop (or segfault)
our program. This might be related to the first commit above.

For now, all this commit does is realize the window manually.

 - Mixing still isn't implemented, but the audio system should be able
   to start up, and mix at least once audio line for the time being.
   Will have to write some test audio sources to verify things are
   working properly, and build the rest of the output functionality.

 - Using a recursive mutex fixes issues where objects need to enter the
   main libobs sources mutex while already within the mutex in the same
   thread.  Otherwise it would keep getting locked on itself on
   destruction.

 - Apply the volume specified with the audio data packet before
   inserting the audio data into the circular buffer.  Added functions
   for multiplying the volume with all the different audio bit depths.
   (Could probably be greatly optmimized later)

Use XGetErrorText() instead of our own table

Another attempt to fix ARB_debug_output, hopefully the last one.

This fixes segfaults when the error code is not in the table

 - Added a volume variable to the obs_source structure and implemented
   functions for manipulating source volume.

 - Added a volume variable to the audio_data structure so that the
   volume will be applied when mixing.

 - Made it so that when a source is added or removed from a scene it
   will add a reference to sourceSceneRefs (std::unordered_map).  Each
   source adds a reference to that every time they are added to a scene,
   and releases a reference from it when they are removed from a scene.

   When the value reaches 0, the source is no longer in any scenes, and
   is then marked for removal and destroyed.

   Before, I was using the source internal reference counter, which is a
   really bad thing to do because I don't know what might actually be
   referencing it.  So using a separate discrete reference counter for
   the number of scenes it's in is better in this case.

 - Homeworld apparently removed a number of unnecessary sizers from the
   basic UI window form to reduce wx resize computations.

 - Check the actual debug extension instead of checking GL 4.0 support;
   it appears that despite having GL 4.0 support, AMD does not implement
   the standard debug extensions even when the *_CONTEXT_DEBUG_BIT_ARB
   flag is set on the context.

 - Also, fixed a place where spaces where used for indents instead of a
   tab.

 - Removed the dependency on windows.h for windows.  I feel it's an
   unnecessarily large dependency to have to add to all source files
   when the only thing that's needed to make the windows version compile
   the debug functions is just the __stdcall call convention keyword.

   On top of increasing compile time due to the large number of headers
   it includes from all the windows API headers, it also adds a lot of
   potential name conflicts, as I was getting a number of name conflicts
   for lots of names like near/far, which were used in old legacy 16bit
   windows code.

Various Changes to OpenGL intialization

 - Made is so that libobs is now marked as a dependency for the main
   application project 'obs'.

Revert "Merge pull request #19 from asgeirom/master"

I also fixed autoconf to find wxWidgets 2.9 without user intervention
Removed unused code and added more organization

This reverts commit 27ccb094, reversing
changes made to b7eccedf.

 - When a scene is created it now is automatically selected and switched
   to.