refactor(typeahead): move typeaheadEditable out

Unfortunately, this depends on typeaheadEditable running after the post
linking function of the typeahead directive.

Note this and solve this later.
refactor(typeahead): add TypeaheadController

Maintain feature parity. Some duplicate code.
refactor(typeahead): Remove extra calls to loading
Merge branch 'feature/add-typeahead-controller-pr' of https://github.com/chrisirhc/angular-ui-bootstrap

Conflicts:
	src/typeahead/typeahead.js
ignoring IntellijIDEA files.