Add unparse_url to urllib3.util.url

This round-trips with parse_url (or at least equivalently by the RFC).
Add url attribute to Url, which gives the same thing as unparse_url()
Improve code coverage
Remove unparse_url, in favor of Url.url
Make something a little clearer
pyOpenSSL: Fix WantWrite issue #412
Bounty source.
Set socket options before binding. (#427 again)
Fixed flaky tests. (Closes #408 for now.)
Add a missing contributor
Merge pull request #433 from sigmavirus24/add-self-to-contributors

Add a missing contributor.
is_fp_closed checks .closed first
added tests for is_fp_closed
make attr check consistent, fix punctuation
Merge pull request #435 from novocaine/is-fp-closed-checks-closed-first

Is fp closed checks closed first.
CHANGES for #435
Packaging: Tweaking MANIFEST.in to add missing files.

Fixes #440, I hope?
CHANGES for #440
Add do the HTTPResponse docstring to give some info about `io` compatibility
Add `io` example under usage