Code review comment for lp:~garyvdm/qbzr/newwtlist

This replaces wtlist with treewidget in qcommit, qadd, and qrevert.

To do this I have added a mode to the treewidget called changes_mode. This only
show changes, and not the whole tree. Like the old wtlist, changes from subdirs
are shown in the root, e.g.

In normal mode, you would see:
Dir1
  File1 Modified

but in changes_mode, you will see:
Dir1/File1 Modified

Unless a parent directory is shown, which may happen if you have a unversioned,
added, or renamed directory.

e.g. in changes_mode, you will get:

dir1 => dir2 Renamed
  File3 Modified

dir4 Added
  file5 Added

Drive by improvement: qcommit now adjusts the auto complete word list if you
change which files are selected in the file list.

Some screen shots:

http://garyvdm.googlepages.com/qcommit_new_widget.png
http://garyvdm.googlepages.com/qadd_new_widget.png