Response and Request objects are pickleable.

Includes a basic test. More could be add to confirm known attributes
that could cause problems.
Wheel support.
Add wheel to dev requirements.
loosen URL handling for non-native URL schemes
Merge pull request #1717 from jvantuyl/master

loosen URL handling for non-native URL schemes
Merge pull request #1735 from Lukasa/wheel

Wheel
add coverage make target
Merge pull request #1739 from pengfei-xue/devel

add coverage make target
Add target to build the documentation
wording
Small fix broken cookie parse
issue #1746 : Don't lowercase the whole URL!
use geturl to lower scheme
Merge pull request #1745 from nonm/master

Small fix broken cookie parse
Merge pull request #1733 from ionrock/pickleable-responses

Response and Request objects are pickleable.
Merge pull request #1742 from kevinburke/docs

Add make target to build the documentation
Merge pull request #1747 from daftshady/lowercase

#1746 don't lowercase the whole url
Handle 301s 'properly'.
Cleanup the redirect if blocks.
Fix hangs on streaming uploads with HTTPDigestAuth

When using Digest Authentication, the client resends the same request
after the server responds with the 401 "Unauthorized". However, when
doing streaming uploads, it gets stuck because the body data (a
file-like object) is already consumed at the initial request.

The patch fixes this by rewinding the file-like object before
resending the request.