Set the text of a UISearchBar if a keyboard character can't be found.

This seems to be related to #263. KIFUITestActor already manually sets the text
in a UITextField and a UITextView when a character cannot be found, so
this change includes UISearchBar as a view whose text can be manually
set if needed.

This workaround serves my purposes, so I figured I would share.

Just for some background, I'm having the "Failed to find key for character" error occur when entering text into a UISearchBar with ~340 items in its corresponding UITableView. I think @plu is correct is his assumptions about the search/core data delay.

Also, as a note, with a fresh clone of KIF for me, the LongPressTests failed in afterEach and in testLongPressingViewViewWithValue. After this change, all the tests passed except those same 2.