Fixed wrong behaviour when input step leads to end value higher then max value
Fixed wrong coords math rounding method in getValueFromPosition
Fixed ceiling instead of rounding issue.

Fixed case where range has a lot of values and step is < 2px - in such case you will be able to choose any of the steps by mouse, but then the range will change it to following step.
Merge commit 'a6b333cbe1dff' into develop
Merge commit '98e66a03fdc9c81995b1' into develop

Conflicts:
	dist/rangeslider.min.js
	src/rangeslider.js

I didn't merge the files in dist/