Fix bug #2961 (Documents may leak due to listeners left on FileEntry) -
Simplify by just directly pinging refcounted documents from
DocumentManager.notifyPathNameChanged(). FileUtils no longer triggers a
"rename" event on FileEntry objects and we no longer have a per-Document
listener.

Also, enable block comments in XML files.
Update unit test to account for the #2961 fix. Previously, the test was
emulating rename by doing less than ProjectManager.renameItem() does in the
real world. Due to the memory leak fix, the now need a closer imitation.
fix tab indentation
Merge pull request #2984 from adobe/pflynn/document-listener-leak

Fix #2961 (Documents may leak due to listeners left on FileEntry)