Fixes several files incorrectly stated a different license from the actual project, as well as the copyright headers included in all files. This change has no effect on the licensing terms, it should clear up a bit of confusion by contributors. Plus the files get a bit smaller, and we have less duplicated information across the entire project.
Overall the project is GPLv2 if not built with Qt, and GPLv3 if it is built with Qt. There are no parts licensed under a different license, all have been adapted from other compatible licenses into GPLv2 or GPLv3.
Changes applied:
* Moved utility files to /util/.
* Removed unused #includes.
* Removed unused ::ffmpeg::tools function.
* Removed unused variables.
* Fixed missing parentheses in the version macro.
* Fixed missing override on virtual function overrides and removed unnecessary virtual keyword from them.
* Disabled additional warning for ATL headers on MSVC only.
* Replaced direct printf parameters with their macro equivalent.
* Replaced C-style casts with C++-style casts.
* Applied clang-format again after an earlier change to the CMake file broke the integration for it.
With this, GCC 8 and above should now be able to compile the project both in obs-studio and as a standalone install. Some features are currently still not fully supported and require extra work, but the majority of things are supported and work out of the box. Exact feature parity can be looked up here on the wiki: https://github.com/Xaymar/obs-StreamFX/wiki/Platform-Feature-Parity
Related: #119#98#30
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/.
