Grunt 'rename' fix

There was an issue that cropped up when you used Grunt's [rename](http://fettblog.eu/blog/2014/05/27/undocumented-features-rename/) function in the grunt config. Instead of saving the file to the desired location, it would create a folder at that location and save the icon within it, preceded by the CWD folder structure.

Reading that back, it makes very little sense (apologies, I'm a little hungover today), try it it out though and you'll see what I mean.

I've popped in some tests, updated the config and squashed the bug though.