Lets users remove hover styles on touch devices with one variable and modernizr

Let less users prefix hover states with .no-touch by adding it to @hover-prefix in variables.less which by default is just an empty string

This fixes unwanted hover states on touch devices (http://www.nczonline.net/blog/2012/07/05/ios-has-a-hover-problem/)

I did compile the less using grunt and it produces no changes unless you add .no-touch to @hover-prefix in variables, that isn't the default so there are no changes reflected in the compiled/minified css. 

Tested on ios 6 in Chrome & Safari.

Perhaps it should be an option in http://getbootstrap.com/customize/ ?