add PAL flag to dispatch

now platforms run at their correct clock speed when in PAL mode

also fix clipping in Genesis

src/engine/platform/abstract.cpp

@@ -18,6 +18,6 @@ bool DivDispatch::keyOffAffectsArp(int ch) {
   return false;
 }
 
-int DivDispatch::init(DivEngine* p, int channels, int sugRate) {
+int DivDispatch::init(DivEngine* p, int channels, int sugRate, bool pal) {
   return 0;
 }