Minifier was breaking CSS/LESS with assets with spaces in names

The URL rewriter wasn't using quotes, which broken font or image names
that were in the local path using spaces in the name.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)
Merge pull request #572 from enyojs/fix-minifier-spaces

Minifier was breaking CSS/LESS with assets with spaces in names