BETA 0.5.0 update

updates how observablelists/cursors work
updates spinner and listview support
added relative context
added more to demo app
updated iproxyobservableobject (no need to implement getSource())
stream lined flags in BindingInventory.
Add convenient objects for handleing multi selection on lists and
cursors
updated how extensions to cursors work
Added property listener to listen to specific property updates on
objects
updated some attributes for layouts.
now supports include/merge tags