Fix displaying documents in the document browse and refreshing the selection
when the results have changed.
Make sure we are passing the appropriate flag to _redisplay() in GenericDisplay.
Make sure we set this._appsStale to true if there was a change in the
applications set.
Don't call _refreshCache() from the AppDisplay constructor.
Don't short-circuit the call to _refreshCache() from _redisplay() on initial load.
Rename _redisplayFull() to recreateDisplayItems() and remove adding an
actor to the actual result list in _addDisplayItem() because we redo adding the
actors to the list in _redisplayReordering() anyway to ensure that we add
them in the right order.
Based on a patch from Colin Walters.
eb8176deeb