Patch for include css files via @import url(xxx); 

As we have very large CSS files and need to be OK with IE 8, we had to split the CSS in several files (using blessCss auto splitting) to not exceed the 4095 CSS selectors limitation on IE. But we also have to use media-queries... I developped this little patch, basically what it does :
- for every css file, check using regexp if there is an @import url(xxx);
- if there is imported files, I put them in the queue (first in line), and put back the current file in the queue right after them
- continue the queue without proceeding the importING file -> it continues with the newly added imported file
- etc...