rtmp-services: Add Twitch Salt Lake City ingest

Noise Suppression: Clamp sample values before converting to integer.
This fixes an issue where samples exceeding full scale would overflow,
resulting in heavy distortion.

Closes jp9000/obs-studio#1113

Scene filters were not being copied when a scene was duplicated with
obs_scene_duplicate.

Closes jp9000/obs-studio#1104

(This commit also modifies the UI)

The source release was being done in the wrong file.

UI: Fix minor Rachni theme bugs

This would fail to release the reference if the 'direct' parameter was
used.

Closes jp9000/obs-studio#1116

vec4_set was the equivalent to vec2_set.

Closes jp9000/obs-studio#1115

(Windows only)
3rd party antivirus / firewalls cause a large number of issues in OBS.
Logging which products are installed will help narrow down potential
issues when users ask for help and include their log files.

Closes jp9000/obs-studio#1124

Closes jp9000/obs-studio#1127

Adds a scripting tool that gives the users the ability to load scripts
and change their settings.

Allows Lua/Python scripting support.

Allows the ability to pass private data to a callback (useful
specifically for scripting purposes).

Allows passing button-specific private data to the button callback
rather than just passing the private data of the properties object.

The function in the header was marked as just inline, which would cause
processing problems for SWIG.

Prevents SWIG from being able to process certain declarations that would
cause binding generation errors/warnings.

Implements the OBS_SOURCE_CAP_DISABLE capability flag in to the user
interface.

This event is called when all scene data has been unloaded.

When the program first starts up, or rather when a scene collection is
loaded, the frontend API OBS_FRONTEND_EVENT_SCENE_CHANGED event would
not get triggered.

Allows safely removing callbacks from within the callbacks themselves.

Allows loading data before actually loading any scene data.

Allows for projects other than UI to be able to reference these CMake
variables.

The "obs" global variable can still be accessed by functions during
shutdown.  To prevent access to the variable during shutdown, move the
pointer to a temporary function variable, and set the "obs" global
variable to NULL before shutting down.

Individual property objects would store pointers to strings rather than
copies of the strings and assume that memory would continue to exist, so
instead just duplicate the strings.

Because it would be troublesome to add the ability to remove source
types (in case for example a script fails to reload), instead make it so
source types can be temporarily disabled while the program is running.

A global callback allows capturing all signals from a signal handler
rather than just a specific signal.

Convenience function that allows removing the current signal handler
callback within the callback without having to use
signal_handler_disconnect with all of its required parameters.

Adds a thread local storage macro to declare thread local storage
independent of platform.

Allows the ability to have a callback invoked every time video ticks.
Particularly useful for scripting.

This is mostly for win32-specific files

SWIG will fail because it doesn't define _MSC_VER and because it doesn't
know what to do with things like __attribute__.

When splitting a string in to a string list via stringlist_split, it
would previously allocate memory for each sub-string and again for the
list itself.  This optimizes that function to use a single contiguous
chunk of memory for the sake of access optimization and memory
allocation efficiency.

Uses type_data to get the type-specific data of a source type

Uses type_data to get the type-specific data of a source type