Initial commit
Add generated item provider adapter factories for Ecore and EXTLibrary.
Add item provider decorators to change the labels of all "item" subclass
at one location without modifying the generated code.
Modify the tree display of the library model.

Use TreeNode in the tree (changed the input of the viewer).
Change all EXTLibrary item providers to stateful type to avoid
unnecessary notifications.
Add capitalization capability on Writer to show that notifications are
correctly propagated.