Updated highlight module to remove 'unsafe' from ng-html-bind

Relates to:
https://github.com/angular-ui/ui-utils/issues/174
https://github.com/angular-ui/ui-utils/pull/332
https://github.com/angular-ui/ui-utils/pull/333
https://github.com/angular-ui/ui-utils/pull/278
https://github.com/angular-ui/ui-utils/pull/277

You can test highlight here here:
http://f1lt3r.github.io/ui-utils/

Should look like this:
![screen shot 2014-12-18 at 2 14 31 pm](https://cloud.githubusercontent.com/assets/1218446/5494233/3c56c6e2-86c0-11e4-8f54-1c61c91e9bbe.png)