Various updates for the search bar, fixing bugs and tidy

* Fix a bug where if there is no predicate set, entering a search then
  hitting backspace would still result in the previous search
* Don't set content offset while we are decelerating from scroll
* Allow search bar to be set from a nib
* Don't hardcode size of search bar, (iPad?)
* Remove weird unused scroll directions
* Fix some \t vs whitespace