- Add saturnpak, saturnjoin, screenfbo settings
- Add libbacktrace stuff (hope thats correct)
- set openmpt, discordrpc and libbacktrace as optional libs
- move asset hashes to d_main, fixing CMAKECONFIG (which fixes commit stuff)
- propely handle md5 sources
- set "-rdynamic" and "-g" (-g1 on non debug builds) so libbacktrace can get proper backtraces