urlRewriter will expect a callable as a second parameter,
but will work with the current api and simply raise a deprecation error.
HTTP::absoluteURLs now correctly rewrites urls into absolute urls. Resolves introduced in c56a80d6ce
HTTP::absoluteURLs now handles additional cases where urls were not translated.
Test cases for HTTP::absoluteURLs added for both css and attribute links.
Cleaned up replacement expression and improved documentation.