Instead of synchronizing the main list and the list of entries in the
dialog, just remember what was added and removed and only add / remove
those entries in the main "SvxAutoCorrect" list.
Additional add MakeCombinedChanges which adds and remove entries in
one call and only writes changes to the "acor" file once.

Change-Id: Idcc4c64d25e050c3f6eb9960a59c4a55d06b5ca1