updated include paths (CMake+osxtest) and function prototype (osxtest)

fixes compilation with changes from e5c99175c55e3b08493058d4aefcf31f62018ac1
added os_get_home_path and os_mkdir to osx cocoa platform
With the permission of my fellow contributors, I'm switching obs-studio back to GPL v2+ to prevent issues between this project and the original OBS project, and for personal reasons to avoid legal ambiguity (not political reasons, I admittedly would prefer GPL v3+)
added functions to get current audio/video output information
updated UI files
made it so that preview panel scales based upon window size
moved wx forms and generated files into a discrete 'forms' directory
fix references to subclass files within forms
change naming for some main program files for consistency
update makefiles for previous name changes
compile libobs with -fobjc-arc
fix format string
check for __APPLE__ instead of __WXCOCOA__
fix warning for OBSSource::operator=