hgweb: Pass only filename instead of full path when downloading raw files.
Before this patch "filename=foo/bar" was sent and e.g. Firefox offered to save
the file as "foo-bar" instead of just "bar".
To run the tests, do:cd tests/python run-tests.pySee http://www.selenic.com/mercurial/wiki/index.cgi/WritingTests formore information on writing tests.