yeoman/grunt-usemin — pull request #231 by imorrison (2013-11-12 23:14:20+00:00)
Title: Makes quotes optional for inlined background url

I noticed that this regex was not swapping out some image references in a project that I am working on. The reason was some inlined css that did not use quotes for background images. So I have modified the regex to work like the one for processing css.