Works better within the context of an angular form

Fairly large refactor. Includes the following:

* Uses ngModelController to interact with ngModel
* Properly sets surrounding form as $dirty or $pristine
* Ability to add a required validation. Will set self
and surrounding form as $valid or $invalid accordingly.
* Uses standard ng-invalid css classes instead of custom ones
* Bumped version up to 1.3.0-beta
Minor cleanup and commenting
Removed the watch on ngModel

and replaced it with $viewChangeListeners and $render
Removed ng-invalid from button because it already is

being applied to the surrounding div
Changed version from beta to alpha
Changed download link back to stable version
Merge branch 'master' into better_form_citizen

Conflicts:
	bower.json
	dist/ng-quick-date.min.js
	package.json