Retain presetSelector and its SettingsChanged event handler
Retain presetSelector and its SettingsChanged event handler

- Issue MatterHackers/MCCentral#3134
Changing material setting in main slice settings does not update
extruder material selection

mmoening/MatterControl,larsbrubaker/MatterControl,jlewin/MatterControl,jlewin/MatterControl,mmoening/MatterControl,mmoening/MatterControl,unlimitedbacon/MatterControl,larsbrubaker/MatterControl,larsbrubaker/MatterControl,jlewin/MatterControl,unlimitedbacon/MatterControl,jlewin/MatterControl,larsbrubaker/MatterControl,unlimitedbacon/MatterControl,unlimitedbacon/MatterControl