Adds a new CMake option "ENABLE_PROFILING" which enables all CPU and GPU performance profiling available in StreamFX for tracking what's actually causing things to be slow.
To further distance the code from having to do too much manually, the graphics context is now available as a managed class. All places that previously used obs_enter_graphics and obs_leave_graphics are now using the new gs::context class instead.
The number of files in the source directory was a little bit much and just made file naming more complex than it had to be. Therefore all files were moved into subdirectories where it matters.
Filters now reside in source/filters/, Sources in source/sources/, OBS Wrappers in obs/, OBS GS Wrappers in obs/gs/, Transitions will reside in source/transitions, Graphics Helpers will be in gfx/.
