When the new UI was put in, the action shortcuts were unintentionally
removed from the list boxes.

Apparently using QPointer container for the QObject being given to the
connect function makes it so it can't find the actual function to use.
I'm guessing this is incomplete functionality or a bug that existed in
GCC 4.8.  Doesn't happen in 4.9+.

Implements transitions, and introduces "Studio Mode" which allows live
editing of the same or different scenes while preserving what's
currently being displayed.

Studio Mode offers a number of new features:
  - The ability to edit different scenes or the same scene without
    modifying what's currently being displayed (of course)

  - The ability to set up "quick transitions" with a desired transition
    and duration that can be assigned hotkeys

  - The option to create full copies of all sources in the program scene
    to allow editing of source properties of the same scene live without
    modifying the output, or (by default) just use references.  (Note
    however that certain sources cannot be duplicated, such as capture
    sources, media sources, and device sources)

  - Swap Mode (enabled by default) which swaps the program scene with
    the preview scene when a transition completes

Currently, only non-configurable transitions (transitions without
properties) are listed, and the only transitions available as of this
writing are fade and cut.  In future versions more transitions will be
added, such as swipe, stingers, and many other various sort of
transitions, and the UI will support being able to add/configure/remove
those sort of configurable transitions.

(Note: This commit also modifies the UI)

Allows the ability to duplicate sources fully copied, and/or have the
scene and its duplicates be private sources

(Note: This commit also modifies UI)

Instead of using signals, use designated callback lists for audio
capture and audio control helpers.  Signals aren't suitable here due to
the fact that signals aren't meant for things that happen every frame or
things that happen every time audio/video is received.  Also prevents
audio from being allocated every time these functions are called due to
the calldata structure.

(Note: test and UI are also modified by this commit)

API Changed (removed "enum obs_source_type type" parameter):
-------------------------
obs_source_get_display_name
obs_source_create
obs_get_source_output_flags
obs_get_source_defaults
obs_get_source_properties

Removes the "type" parameter from these functions.  The "type" parameter
really doesn't serve much of a purpose being a parameter in any of these
cases, the type is just to indicate what it's used for.

(Note: This commit breaks libobs compilation.  Skip if bisecting)

Closes jp9000/obs-studio#499

OSX has an annoying feature called "BeamSync", which on later versions
of OSX is always on.  For whatever reason, Apple devs decided to force
this feature to always be on, so applications must always render with
v-sync regardless of what they set their swap interval to.

This issue would cause syncing to the vertical refresh for each
additional active display, and wouldn't allow rendering above the
current refresh rate.  This caused major rendering stalls and prevented
video frame timing from being accurate.

This fixes the issue by using an undocumented set of functions to
disable BeamSync.  Note that because this is an undocumented method of
working around the issue, its existence cannot be guaranteed.  If the
functions no longer exist for whatever reason, it will safely do
nothing.

Also hide adapter list if not using Direct3D.

These really are advanced options that users shouldn't need to change
normally, so moving them to advanced makes sense, and keeps them away
from users who don't know what they're doing.

If the base resolution is set to an invalid resolution, it would cause
the output resolution to automatically change to an invalid resolution.
After the invalid resolution was set for the output resolution, it would
stay at that invalid resolution.

This fixes it so it always tries to find the output resolution closest
to what was last actually set or actually edited.

When right-clicking items in the preview window and getting context
menus for them, it would often make the wrong scene item be associated
with the context menu because of the fact that it was using
QListWidget::currentItem instead of querying the actual selected list.

You must query the actual selection list via QListWidget::selectedItems
because QListWidget::currentItem does not work properly for
multi-selection list widgets.

Shows a warning stating that encoding is stalling, and shows the number
and percentage of frames that were skipped due to encoding.

If a global audio device is disconnected or for whatever reason is no
longer available when audio settings is opened, it will erroneously
select index 0 of the combo box ("Disabled") by default because it can't
find it in the combo box.  This fixes that issue by making it insert an
item in to the combo box specifying that the previously available audio
device is no longer available, and properly preserving the user's
settings.

Some streamers would accidentally hit start/stop streaming, which on
certain services would send out mass emails to all their followers.
This just adds options to general settings to optionally enable dialogs
that confirm whether to actually start/stop streaming when the button is
clicked.

Because of the patch that removed the "user sources list" in libobs
(70fec7ae), obs_enum_sources will now enumerate the global audio
sources, where it didn't before.  In the advanced audio properties
dialog, before the patch I had to use code to manually include them, but
I neglected to remove that code when I made that patch, so it would
cause them to be added more than once.  This just removes that code.

When you assign a menu to a normal QPushButton, it becomes a button that
only allows you to have a menu.  This class lets you click the button
and have a menu at the same time.

Fixes a bug where the preview's size calculations wouldn't update if the
widget itself was resizes but the window wasn't resized.

Allows adjusting the size of the bottom section of the main window

Prunes code used to workaround libobs "user sources" (such as
sourceSceneRefs) and instead simply holds its own references and saves
sources it chooses with obs_save_sources_filtered.

(Note: This commit breaks UI compilation.  Skip if bisecting)

Ensures that a reference is kept until the signals associated with that
reference are disconnected.

This will probably go away once proper file name formatting is
implemented (https://obsproject.com/mantis/view.php?id=361)

Having sleep or screensavers inhibited at all times was causing some
annoyances for people.  Sleep/screensavers are now only inhibited when
the program is active or when a projector is open.

Fixes the following warning:

warning C4505: 'operator ==' : unreferenced local function has been
removed

This function actually is used despite this warning, so the only way to
get rid of the warning is to disable the warning itself in this
particular case.

Allows changing item selection via list box or via preview window, and
keeps their selection status in sync with each other.

The unsupported part should basically be signaled via making that
value inaccessible