Add whole-word option in model and view

The state is serialised, but the option is not used yet.
Implement whole-word search in the model
Add key bindings for the whole-word option
Change the label for the whole-word option
Add option label for the whole-word option
Merge branch 'feature/whole-word-option' of github.com:abe33/find-and-replace into abe33-feature/whole-word-option

Conflicts:
	lib/find-model.coffee