Add gs_device_name function

This returns the name of the device, "Direct3D 11" or "OpenGL"
respectively.
Add gs_device_type function

This allows a programatic way of determining the type of graphics module
currently active.
Mark menu entries for Qt application menu mangling on OSX
(API Change) obs_reset_video: Use return codes

Changed API functions:
libobs: obs_reset_video

Before, video initialization returned a boolean, but "failed" is too
little information, if it fails due to lack of device capabilities or
bad video device parameters, the front-end needs to know that.

The OBS Basic UI has also been updated to reflect this API change.
Check for valid sizes when initializing video
If Direct3D doesn't initialize, try OpenGL
Add color property implementation
Add OBS_TEXT_MULTILINE for text obs properties
Remove unnecessary compiler flag
Add mac-window-capture