Bug fix: original predicate was not being set until search text entered and then being set to nil on cancel

This resulted in the fetchedResultsController having it's predicate
cleared which returned all elements in the query entity.
Allows work-around for ensuring Cancel button remains enabled
Bug fix: missing required indirection on stop
Merge pull request #35 from kylef/bugs

Bug fix: original predicate was not being set until search text entered ...