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/vic20.cpp

@@ -69,7 +69,7 @@ void DivPlatformVIC20::acquire(short** buf, size_t len) {
     vic_sound_machine_calculate_samples(vic,&samp,1,1,0,SAMP_DIVIDER);
     buf[0][h]=samp;
     for (int i=0; i<4; i++) {
-      oscBuf[i]->data[oscBuf[i]->needle++]=vic->ch[i].out?(vic->volume<<11):0;
+      oscBuf[i]->data[oscBuf[i]->needle++]=vic->ch[i].out?(vic->volume<<10):0;
     }
   }
 }