refactor(rating): compatibility with AngularJS 1.2
style(buttons): cleanup button formatting

Normalize spacing issues
feat(datepicker): datepicker-append-to-body attribute

Attribute / option specifies where in the DOM to place the datepicker
popup elements.

If this option evaluates to 'true', the datepicker popup elements are
appended to 'body'. Otherwise, they follow the directive element.