add "hint" commands

src/engine/dispatch.h

@@ -55,6 +55,14 @@ enum DivDispatchCmds {
   DIV_CMD_PRE_PORTA, // (inPorta, isPortaOrSlide)
   DIV_CMD_PRE_NOTE, // used in C64 (note)
 
+  // these will be used in ROM export.
+  // do NOT implement!
+  DIV_CMD_HINT_VIBRATO, // (speed, depth)
+  DIV_CMD_HINT_VIBRATO_SHAPE, // (shape)
+  DIV_CMD_HINT_PITCH, // (pitch)
+  DIV_CMD_HINT_ARPEGGIO, // (note1, note2)
+  DIV_CMD_HINT_VOL_SLIDE, // (amount, oneTick)
+
   DIV_CMD_SAMPLE_MODE, // (enabled)
   DIV_CMD_SAMPLE_FREQ, // (frequency)
   DIV_CMD_SAMPLE_BANK, // (bank)

src/engine/playback.cpp

@@ -57,6 +57,12 @@ const char* cmdName[]={
   "PRE_PORTA",
   "PRE_NOTE",
 
+  "HINT_VIBRATO",
+  "HINT_VIBRATO_SHAPE",
+  "HINT_PITCH",
+  "HINT_ARPEGGIO",
+  "HINT_VOL_SLIDE",
+
   "SAMPLE_MODE",
   "SAMPLE_FREQ",
   "SAMPLE_BANK",