a lot of work

- round to nearest instead of round to zero in SMS period calc
- implement arpeggio
- implement arp macro (kinda)
- polish the SMS platform
- correct the DIV_CMD_PITCH range to 1 semitone
- fix PSG volume in Genesis
- use a better register write strat in Genesis
- fix a bug caused by legacy code
- implement ECxx command
- implement EDxx command
- implement SN noise mode command
- vibrato table is now 64 positions long (instead of 60)

src/engine/engine.cpp

@@ -668,8 +668,8 @@ bool DivEngine::init() {
   bbOut[0]=new short[got.bufsize];
   bbOut[1]=new short[got.bufsize];
 
-  for (int i=0; i<60; i++) {
-    vibTable[i]=127*sin(((double)i/60.0)*(2*M_PI));
+  for (int i=0; i<64; i++) {
+    vibTable[i]=127*sin(((double)i/64.0)*(2*M_PI));
   }
 
   switch (song.system) {