Packets were not interleaving, thus new data was being sent out with
potentially non-monotonically increasing timestamps

Improve bundle fixup

Before, async video sources would flicker because they were only being
drawn when they were updated.  So when updated, they'd draw that frame,
then it would stop drawing it until it updated again.  This fixes that
issue and they should now draw properly.

Also, fix a few other minor bugs and issues relating to async video,
and make it so that non-async video filters can be properly applied to
them.

For the purposes of testing, change the 'test-random' source to an async
video source that updates every quarter of a second with a new random
face.

Also fix a bug where non-async video sources wouldn't have filter
effects applied properly.

Was wrong to use the swizzle -- it was an incorrect assumption on my
part that this could work in the first place (despite working on
windows)

Linux fixes and additions

A little bit of history about frame dropping:

I did a large number of experiments with frame dropping in old versions
of OBS1, and it's not an easy thing to deal with.  I tried just about
everything from standard i-frame delay, to large buffers, to dumping
packets, to super-unnecessarily-complex things that just ended up
causing more problems than they was worth.

When I did my experiments, I found that the most ideal frame drop system
(in terms of reducing the amount of total data that needed to be
dropped) was in the 0.4xx days where I had a 3 second frame-drop buffer
where I could calculate the actual buffer size in bytes, and then
intellgently choose packets in that buffer to trim it down to a specific
size while minimizing the number of p-frames and i-frames dropped, and
preventing the actual impact of dropped frames on the stream.  The
downside of it was that it required too much extra latency, and far too
many people complained about it, so it was removed in favor of the
current system.

The current system I just refer to just as 'packet dumping', which when
combined with low keyframe intervals (like most services use these
days), is the next-best method from my experience.  Just dump the buffer
when you reach a threshold of buffering (which I prefer to measure with
time rather than in size), then wait for a new i-frame.  Simple,
effective, and reduces the risk of consecutive buffering, while still
having fairly low impact on the stream output due to the low keyframe
interval of services.

By the way, audio will not (and should not ever) be dropped, lest you
end up with syncing issues (among other nasty things) specific to server
implementation.

On some operating systems, with specific drivers it seems that BGR/BGRA
isn't properly treated as such in certain cases.  This fix will
hopefully force the formats to be treated as BGR/BGRA when actually
rendering, which should get around the implementation-specific issue.

 - Fix an issue that could occur when using more than one video encoder.
   Audio/video would not sync up correctly because they were expected to
   be paired with a particular encoder.  This simply adds a little
   helper variable to encoder packets that specifies the system time in
   microseconds.  We then use that system time to sync

 - Fix an issue with x264 with fractional FPS rates (29.97 and 59.94
   particularly) where it would create ridiculously large stream
   outputs.  The problem was that you shouldn't set the timebase_*
   variables in the x264 params manually, let x264 handle the default
   values for it and leave them at 0.

 - Make x264 use CFR output, because there's no reason to ever use VFR
   in this case.

Fixes debug compilation on non-WIN32 targets due to undefined
netstackdump(_read) symbols

 - Implement the RTMP output module.  This time around, we just use a
   simple FLV muxer, then just write to the stream with RTMP_Write.
   Easy and effective.

 - Fix the FLV muxer, the muxer now outputs proper FLV packets.

 - Output API:
   * When using encoders, automatically interleave encoded packets
     before sending it to the output.

   * Pair encoders and have them automatically wait for the other to
     start to ensure sync.

   * Change 'obs_output_signal_start_fail' to 'obs_output_signal_stop'
     because it was a bit confusing, and doing this makes a lot more
     sense for outputs that need to stop suddenly (disconnections/etc).

 - Encoder API:
   * Remove some unnecessary encoder functions from the actual API and
     make them internal.  Most of the encoder functions are handled
     automatically by outputs anyway, so there's no real need to expose
     them and end up inadvertently confusing plugin writers.

   * Have audio encoders wait for the video encoder to get a frame, then
     start at the exact data point that the first video frame starts to
     ensure the most accrate sync of video/audio possible.

   * Add a required 'frame_size' callback for audio encoders that
     returns the expected number of frames desired to encode with.  This
     way, the libobs encoder API can handle the circular buffering
     internally automatically for the encoder modules, so encoder
     writers don't have to do it themselves.

 - Fix a few bugs in the serializer interface.  It was passing the wrong
   variable for the data in a few cases.

 - If a source has video, make obs_source_update defer the actual update
   callback until the tick function is called to prevent threading
   issues.

Caused D3D11 library to fail on load.  Don't know how I didn't see this
sooner.

Someone got rather confused over what the "default" functions did, so
hopefully this clears it up a bit.

I was getting cases where the CPU cache was causing issues with the
allocation counter, for the longest time I thought I was doing something
wrong, but when the allocation counter went below 0, I realized it was
because I didn't use atomics for incrementing/decrementing the
allocation counter variable.  The allocation counter now always should
have the correct value.

Now that we have the priorties window in we can finally be able to
select windows for capture source such as window capture.  Only took
about an hour or two to write.

Also, fixed some depednency issues on winmm.lib with obs-outputs

More extensions, less bugs

Added GLX_NV_copy_image extension, updated tools

Add compatiblity for some older ffmpeg versions

...I think I need sleep.  That last commit before this one shows it
quite clearly.

Accidentally removed a function from the main module declaration macro.

Instead of doing this, just use macros to handle this situation.

Also, fix a minor bug in AAC encoder

This just adds FFmpeg's default AAC encoder as an audio encoder.  Going
to try to start getting things going with the RTMP output library next.

 - Add interleaving of video/audio packets for outputs that are encoded
   and expect both video and audio data, sorting the packets and sending
   them to the output when both video and audio is received.

 - Combine create and initialize callbacks for the encoder API callback
   interface.