Merge pull request #25 from rovolution/master

Merging in EventsSpec, PublicMethodsSpec, and fixing slider source code
adding grunt cli to travis
Update README.md
Update README.md
Update README.md
added element data attribute tests
Fixed slider.less compile errors
Compiled slider.less to slider.css
Fixed border radius

Old value was 20px, less file for some reason used 4px, I think it's
better to use 50%.
Fixed round border

Original value: 20px
Less value: 4px
I think it's better as 50%
Added .slider-disabled to slider.less

Class needed for disabling
Disabled sliders with class slider-disabled

(still have to manually give them the slider-disabled class for now)
Added disabling, enabling, toggling functionality
Added isEnabled, better toggle, removed stupid data stuff.
Changed data-enabled to data-slider-enabled
Added specs for anything added for disabling

data-slider-enabled, enable, disable, toggle, and isEnabled
Updated README.md with new features
Added disabling example to index page
Added disabled slider event tests, fixed mouseup event
Added events for enabling/disabling + tests