extract_links() bug fix: don't allow < and >
add util.update_scheme()
assert_multiline_equals(): squeeze repeated blank lines
init testbed mail stub
update_scheme(): use the current request, not appengine_config
expect_urlopen(): raise HTTPError if expected status is 4xx or 5xx
assert_equals() bug fix: reported lists as equal when one was a prefix of the other

wow. that's been there for a long time. i'm now scared for the correctness of all of my code that's tested with this lib. sigh!