Convert from more music file formats.

[adambiser]

Research converting songs from DRO, CMF, Doom's MUS format, etc.

[adambiser]

MUS format is supported in the Python 3 version that is not yet live on github.

[Wohlstand]

Note that CMF files needs a rhythm-mode support. If you'll implement it, then, it's will be possible to allow rhyth-mode drum instruments from WOPL files. One note: drum instruments inside of CMF are having inverted snare and cymbal registers in comparison with a normal behavior (that is used in WOPL and IBK formats), I have left a note for that:
https://github.com/Wohlstand/libADLMIDI/blob/master/src/adlmidi_opl3.cpp#L135

[adambiser]

I saw that CMF needed rhythm-mode support. Thanks for the note about the drum inversion.

[Wohlstand]

Oh, I think, better word is here "swapped", not "inverted"