Added information about HTTP proxy authentication to docs
Merge pull request #643 from gwrtheyrn/docs_proxy_auth

Added information about HTTP proxy authentication to docs
Allowing hooks to return responses that indicate errors

Since response objects for failures (4xx/5xx responses) evaluate to False
in a boolean context, any hook which returns such a failure response will
evaluate to False.

The way hooks were setup, any failure response resulting from a hook would
be ignored, and the initial response before it got processed by the hook
would be substituted in its place. This commit changes that logic to test
for None so that hooks that return failures can do so.
Implement GSSAPI/Kerberos authentication for requests

Currently has two issues which may be related:
- doesn't work with redirects, we try to authenticate the server a second
  time with a fully completed kerberos context.
- 403 responses result in the wrong response object being returned, but
  this is also true for http digest authentication due to a bug in hook
  handling in general.
Merge pull request #646 from mkomitee/hooks

Allowing hooks to return responses that indicate errors
Auto-detect CA Cert path instead of requiring users to hack setup.py

Also fixed nearby comments to wrap at 79 characters as per PEP8
Merge pull request #651 from urbanairship/detect-cacerts

Auto-detect CA Cert path instead of requiring users to hack setup.py
Revert "Auto-detect CA Cert path instead of requiring users to hack setup.py"

This reverts commit 62a23bfbdecf54e13e571237df5a175e53d539cb.
v0.13.1
Added r.json documentation (document ALL the awesome features!)
In fact, the feature is so awesome that it should go into index.rst
Revert "In fact, the feature is so awesome that it should go into index.rst"

This reverts commit f968fe013659b9b5b89f0316203de5f3139a7217.
more examples

#657
Allow passing a file or file-like object as data.

The underlying httplib already allows passing an open file object as body
to its HTTPConnection.request method. I think requests should allow that
as well.
If this comment is true (https://github.com/kennethreitz/requests/issues/239#issuecomment-6180706), then it would be good to point people in the right direction. Otherwise disregard this message.
Merge pull request #665 from dalanmiller/patch-2

If requests.async has been removed, the docs should point people to the right place.
test that empty body text responses work
make empty body text responses work

#660
Merge remote-tracking branch 'origin/develop' into develop
fix unicode literal for python 3