Merge pull request #444 from akumanatt/x16

VERA: halve output volume to match other PSGs

src/engine/platform/vera.cpp

@@ -414,7 +414,7 @@ void DivPlatformVERA::muteChannel(int ch, bool mute) {
 }
 
 float DivPlatformVERA::getPostAmp() {
-  return 8.0f;
+  return 4.0f;
 }
 
 bool DivPlatformVERA::isStereo() {

src/gui/presets.cpp

@@ -605,7 +605,7 @@ void FurnaceGUI::initSystemPresets() {
   cat.systems.push_back(FurnaceGUISysDef(
     "Commander X16", {
       DIV_SYSTEM_VERA, 64, 0, 0,
-      DIV_SYSTEM_YM2151, 64, 0, 0,
+      DIV_SYSTEM_YM2151, 32, 0, 0,
       0
     }
   ));