Don't memoize status; http_status may change

If the server returns an HTTP status 100, that value will get memoized.
If, on the subsequent continuation request it returns a 200 (as we would expect), the status() method still returns the memoized 100 instead of the newly correct 200, which causes requests to fail with 'connection closed by server'.
fixing specs, cleaning up deprecation warning
there's a helper.rb, moving spec_helper require so it's included in everything
adding a site that supports deflate
Merge pull request #277 from mobilecommons/master

Don't memoize status; http_status may change