docs(concespts): correct spelling and remove unnecessary word
fix($sniffer): $sniffer to support non-vendor prefixes
feat(ngSwipe): Add ngSwipeRight/Left directives to ngMobile

These directives fire an event handler on a touch-and-drag or
click-and-drag to the left or right. Includes unit tests and docs
update. Manually tested on Chrome 26, IE8, Android Chrome and iOS
Safari.