o less CPU usage
	(0.1) now every hi-rev loop's loop count is pre-calculated.
	      (-funroll-loops works)
 o vol0 optimization
	(0.1) different from ST3's, but no side-effect.
o mtm support
	(0.1) done. (but haven't been tested much.)
- keyboard control
- reconsider ovs
- reconsider panning
- remove clicks
	(0.1) partially done. note-off softlands. plays chi_mai.s3m clearer. :)
? graphic user interface
? 16bit output (and change the name to "NSPmodhified" :)
- porting to other systems