m64 format documentation

[nutta]

Great job on this though there's some little things you should change, the 0xFD command doesn't actually delay based on frames, it delays based on ticks though they might work the same way.

Code:

32nd note - 12 ticks 0x0c

16th note - 24 ticks 0x18

8th note - 48 ticks 0x30

4th note - 72 ticks 0x48

2nd note - 96 ticks 0x60

Whole note = 192 ticks 0xc0

4 bars =  0x300