Upgrade to v2

This is my w.i.p. for upgrading to support less.

Please feel free to contribute changes to the branch or add review comments etc. I may be experienced with less, but I'm not super experienced with grunt-contrib-less
@XhmikosR what should maxmin show? input less size and output css ?
Previously it showed output css before and after minimisation..
I just couldn't think of something that is useful, though I guess output size is useful even if input size isn't.