Fixes for meteor (particularly on Windows)

These changes back port some of the changes from the gzippo devel branch.
They are needed to properly pass the root directory and URL suffix to static.send() rather than passing on file names that kind of look like URLs.

The key reason I need these changes is because I am maintaining a Meteor port for Windows, and on Windows things are much more broken because file names have drive letters and backslashes and static.send() never sends the content.