moved all module root model to layer
ui initial
implement add-remove-copy actions for layers. support for changing
use contructor
widget initial
intro layer topic
use in order entries link to layer not rootModel.

due most of methods are delegated of active layer (not owner)
fix bug when layer dont have content entries and it switched from layer where it have
fix bug with invisible combobox items
fix bug when layers dont switched
update on addContentEntry & removeContentEntry
cleanup
help method
invoke module extension listener
dont invoke twice module extension listener
Merge pull request #3 from consulo/CO-56

#CO-56 fixed