Fix for issue #330, wherein you get a confusing exception from HTTPFound.prepare() when you call HTTPFound(location=None).prepare(environ), instead of a clear exception from HTTPFound.init()
Added a unit test that asserts that HTTPFound(location=None) throws a…
Raise a ValueError from HTTPFound.__init__() if location is None.
Actually, please don't merge this right now. I just noticed that my unit test sucks, so I'ma beat the suck out of it and reopen this again in a moment.
Rewrite my unit test to behave correctly w.r.t. different exception t…