* modifying the __all__ line for each override would confuse git as
  each override needs to get seperate approval before comitting.  Because of
  this commits would not always go in in the same order as they are created.
  Also different people working on the same file would start from different
  commit states.  This caused conflicts when patches were merged.
* instead of modifying a single hard coded list we now append to the list
  after each override.  This creates distinct blocks of changed text
  which will not conflict