Fix for http import in less

There are two issues in the original code: 
1. less.modules.path.dirname(href) is mangling http(s) urls by removing extra /
2. http(s) is not seen as a absolute url so the current dir is prepended. 

I don't really like the way I solved it but it's the best I can with the Javascript knowledge I have. The sollution is hopefully clear for someone to make a propper fix.