fix E5xx range in old modules

src/engine/engine.cpp

@@ -801,6 +801,12 @@ bool DivEngine::load(unsigned char* f, size_t slen) {
             // effect
             pat->data[k][4+(l<<1)]=reader.readS();
             pat->data[k][5+(l<<1)]=reader.readS();
+
+            if (ds.version<0x14) {
+              if (pat->data[k][4+(l<<1)]==0xe5 && pat->data[k][5+(l<<1)]!=-1) {
+                pat->data[k][5+(l<<1)]=128+((pat->data[k][5+(l<<1)]-128)/4);
+              }
+            }
           }
           // instrument
           pat->data[k][2]=reader.readS();

src/engine/song.h

@@ -33,6 +33,8 @@ struct DivSong {
   //   - changes pattern length from char to int, probably to allow for size 256
   // - 23: ???
   //   - what happened here?
+  // - 20: v11.1 (?)
+  //   - E5xx effect range is now ±1 semitone
   // - 19: v11
   //   - introduces Arcade system
   //   - changes to the FM instrument format due to YMU759 being dropped