- add shader program
- fix that alpha color was stored in red channel in Color4
- fix buffer upload bug

- Improved the wording for the "hidden" UDMF sector flag to make clear that it only hides the sector on the textured automap

- Added option to enable additive paint selecting without holding shift independently from regular additive selecting

- The missing textures checker now finds missing upper/lower textures on 3D floors when the appropriate flags of the Sector_Set3dFloor special are used. Fixes #269

- Textures will now wrap correctly in visual mode when the flag of the Line_SetIdentification special is set in Hexen format. Fixes #271

- Fixed a bug where the unknown texture error checker didn't report unknown textures on sidedefs that were never seen. Fixed #270