Move change image stuff to XTFileViewController
Flat, changes-only file list option
Move repository property to XTFileListDataSourceBase
Merge branch 'master' into flat
Merge fixup
Fix tabs
Check for null FSEventStream
Move more stuff up to XTFileListDataSourceBase
Basic unit test for changes data source
Merge branch 'refs/heads/flat'

Conflicts:
	Xit/XTFileListDataSource.m
Fix crash when switching between QuickLook preview and text view
Add and clarify some style rules