* moves most of the CSS to the host element so that it's easier to customize the skeleton text
* adds auto inherit for border-radius
* moves height to 100% so it will naturally fill an avatar and thumbnail
* adds animated property defaulted to `false`
* removes mode specific styles as they're the same
* changes background to an rgba making it easier to customize
* still works outside of a container element
* adds usage examples for javascript and angular
* moves the width to the parent element making it easier to style
* adds the ability to style the width using CSS
* uses the global theme text color as the background if a custom background is not supplied before defaulting
closesionic-team/ionic-docs#407
