remove hasSampleInsHeader()

- it is only used by MultiPCM
- an alternative approach is in place

src/engine/platform/abstract.cpp

@@ -221,10 +221,6 @@ bool DivDispatch::hasSamplePtrHeader(int index) {
   return false;
 }
 
-bool DivDispatch::hasSampleInsHeader(int index) {
-  return false;
-}
-
 size_t DivDispatch::getSampleMemOffset(int index) {
   return 0;
 }

src/engine/platform/multipcm.cpp

@@ -566,10 +566,6 @@ bool DivPlatformMultiPCM::hasSamplePtrHeader(int index) {
   return (index==0);
 }
 
-bool DivPlatformMultiPCM::hasSampleInsHeader(int index) {
-  return (index==0);
-}
-
 bool DivPlatformMultiPCM::isSampleLoaded(int index, int sample) {
   if (index!=0) return false;
   if (sample<0 || sample>32767) return false;

src/engine/platform/multipcm.h

@@ -130,7 +130,6 @@ class DivPlatformMultiPCM: public DivDispatch {
     size_t getSampleMemCapacity(int index);
     size_t getSampleMemUsage(int index);
     bool hasSamplePtrHeader(int index=0);
-    bool hasSampleInsHeader(int index=0);
     bool isSampleLoaded(int index, int sample);
     const DivMemoryComposition* getMemCompo(int index);
     void renderSamples(int chipID);