CVS commit by mhowell: 

* Added mute function due to popular request. At first my opinion was "why?, mute is redundant for everything but live TV." But then I realised making users happy is my real objective :-)
* Added DCOP function for mute()
* Some cleanup
* Made EngineController do more engine stuff, not much but some


  M +19 -16    app.cpp   1.367
  M +19 -7     enginecontroller.cpp   1.30
  M +16 -1     enginecontroller.h   1.12
  M +3 -16     playlistitem.cpp   1.102
  M +1 -1      socketserver.cpp   1.31
  M +7 -2      amarokcore/amarokdcophandler.cpp   1.26
  M +1 -0      amarokcore/amarokdcophandler.h   1.18
  M +7 -4      amarokcore/amarokdcopiface.h   1.16