Merge branch 'master' of https://github.com/tildearrow/furnace into es5506_alt

* 'master' of https://github.com/tildearrow/furnace:
  sysDef refactor, part 2
  sysDef refactor, part 1 - PLEASE READ NOTE
  prepare for macroInt preview in instrument editor
  GUI: fix #400
  fix metronome in low-latency mode

# Conflicts:
#	src/engine/dispatch.h
#	src/engine/dispatchContainer.cpp
#	src/engine/instrument.h
#	src/engine/song.h
#	src/engine/sysDef.cpp
#	src/gui/dataList.cpp
#	src/gui/gui.h
#	src/gui/guiConst.cpp

src/engine/dispatchContainer.cpp

@@ -315,6 +315,9 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
     case DIV_SYSTEM_ES5506:
       dispatch=new DivPlatformES5506;
       break;
+    case DIV_SYSTEM_DUMMY:
+      dispatch=new DivPlatformDummy;
+      break;
     default:
       logW("this system is not supported yet! using dummy platform.");
       dispatch=new DivPlatformDummy;