when there is external links in content, it does not render correctly.

[JohnKimDev]

for examples, if a CSS contains one of the following

@import url(http://fonts.googleapis.com/css?family=Ubuntu:400,700);
or
@import url(//fonts.googleapis.com/css?family=Ubuntu:400,700);

the cache folder path is added to the front of the URL instead of rending external URLs as it is.