MPS-18736 CellAction_Cut shouldn't cut root nodes
MPS-18737 CutNode and DeleteNode actions should not be applicable to read-only models
MPS-18765 classloading fails in case of isCompileInMps == false && getFacet(CustomClassLoadingFacet.class) == null
Merge remote-tracking branch 'origin/MPS3.0'

Conflicts:
	workbench/mps-workbench/models/actions.mps