CatacombGL 0.5.4 Beta

New in this release:

• Support for Linux was added through the hard work of @GoGoOtaku, who in the process also did the migration to CMake. Additional testing was performed by @NY00123 (Ubuntu), @Alyxx88 (Linux Mint) and @alessioscand (RaspberryPi). The functionality to auto-detect the default location of the GOG Catacombs Pack in the Wine folder was suggested by @stuaxo.
• Fix: close cheat dialog when ESC is pressed. Reported by NY00123.
• Fix: do not split help screen with black bar. Reported by NY00123.
• Fix: border flash color should be magenta in Catacomb 3-D. Reported by NY00123.