Correctly identify cert files.

Resolves issue #1046.
Fix stupid, stupid logic error.
Import basestring.
Tweaked the 'data' param docs to indicate that a file-like object is also supported.
Updated API docs for 'data' param in sessions module to indicate that file-like object is also supported.
Merge pull request #1052 from hozn/apidocs-tweak

Small tweak to API docs to indicate that file-like object supported for data param.
Fixed typo in comment.
Merge pull request #1055 from michaelwheeler/patch-1

Fixed typo in comment.
Update session documentation.
Merge pull request #1049 from Lukasa/master

Correctly identify certificate filenames.
Merge pull request #1059 from Lukasa/sess_docs

Update session documentation.
Fixes url to AUTHORS.rst

and also mention using 'master' as development branch now.
Using 'master' branch for development

I'm assuming you're no longer using a 'develop' branch, as I don't see one on GitHub.
Merge pull request #1062 from philfreo/patch-2

Using 'master' branch for development
Merge pull request #1061 from philfreo/patch-1

Fixes url to AUTHORS.rst
fix POST redirects

the redirect handling logic compares then method to upper-case strings,
so make sure the method gets upper-cased as well.

add a test to POST to /status/302 on httpbin, which fails against httpbin.org
right now.  i'm submitting a pull request over there to fix that right after
this one.  once that's accepted, the new test verifies that the fix works.
remove stuidly annoying email notifications
update test docs
no async anymore
Merge pull request #1064 from rascalking/master

fix POST redirects