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
Merge pull request #31 from rahatarmanahmed/feature-disabled

Feature disabled