change chan osc range - PLEASE READ

as of now the range is ~32768, either from -16384 to 16383, or 0 to 32767.
it previously was -32768 to 32767 (~65536).

this change was made to better suit chips that only output a positive value.
if you are working on a new chip, update your code and shift right by one if necessary.

src/engine/platform/msm6295.cpp

@@ -79,9 +79,8 @@ void DivPlatformMSM6295::acquire(short** buf, size_t len) {
 
     if (++updateOsc>=22) {
       updateOsc=0;
-      // TODO: per-channel osc
       for (int i=0; i<4; i++) {
-        oscBuf[i]->data[oscBuf[i]->needle++]=msm.voice_out(i)<<6;
+        oscBuf[i]->data[oscBuf[i]->needle++]=msm.voice_out(i)<<5;
       }
     }
   }