Merge pull request #900 from stucox/master

Set ASCII-only option in Uglify - fixes #899
Fixed an `undefined` detect result for `ie8compat` in old IE
Merge branch 'master' of https://github.com/Modernizr/Modernizr
Corrected tests following last commit
Merge branch 'master' into supports
Tweak to border-image test value to pass correctly in Opera 12.15