Added support for the slider to step for step values under 1

[mcculloughsean]

The slider only supported stepping by integers because of the use of Math.round, even with data-step being a floating point value under 1.

I added support for percentages that are floating point values if the stepping is under one. I just changed the master stylesheet to make the input box width wider, but a new class could be added when stepping is under 1.

[johnbender]

mcculloughsean,

We had another pull request for supporting the official step attribute for this purpose which I think would be the best route for this. Having said that, we're aiming for stability and platform compat right now so I'm going to close this and add it to the feature list on the wiki page.

Thanks for taking the time contribute and we'll get back adding this in once we hit the 1.0.