Support for windows. Support for baseUrl config option.

[MarkKharitonov]

Normalizing the path on Windows prepends C: and replaces / with \ thus breaking otherwise valid relative urls. This commit fixes it. In addition, it adds support for a new config option - baseUrl. Motivation - the static content is served by jetty running at http://localhost:8080, but the combohandler is served by node.js at http://localhost:8000. Before this change, such scenario was not supported. Now it is.

[evocateur]

Looks like there were some test failures. I'd rather keep the Windows fixes and the baseUrl option separate, but I'll look into the CSS rewriting issues.