Improve documentation of netrc authentication

The documentation does not make it clear that when the credentials
from netrc are used, Requests authenticates with HTTP Basic Auth.

I just spent ages trying to figure out why it wasn't working, and
it was because although the credentials in the netrc were correct,
the server actually required HTTP Digest Auth.

Add a section in the authentication documentation to make it clear
that HTTP Basic Auth is used.
Remove charset from JSON types: not valid.
Move netrc authentication documentation under the Basic Auth section
Merge pull request #1465 from dpursehouse/doc-netrc-authentication

Improve documentation of netrc authentication
Merge pull request #1470 from Lukasa/carset

Remove charset from JSON types: not valid.
Some cosmetic updates to the docs

Signed-off-by: Kwpolska <kwpolska@gmail.com>
Grammar fixes and such

Signed-off-by: Kwpolska <kwpolska@gmail.com>
fixed underline

Signed-off-by: Kwpolska <kwpolska@gmail.com>
session object should be uppercase

Signed-off-by: Kwpolska <kwpolska@gmail.com>
further treatment

Signed-off-by: Kwpolska <kwpolska@gmail.com>
Merge pull request #1474 from Kwpolska/docfix

Some tiny fixes to the documentation
Add copy method to PreparedRequest objects
Wrap long lines in the authentication documentation
Add a simple example of custom authentication in the documentation

Refs #1471
Merge pull request #1477 from dpursehouse/other-auth-basic-example

Add a simple example of custom authentication in the documentation
Add myself to the authors list
Merge pull request #1478 from dpursehouse/add-me-to-authors

Add myself to the authors list
Fix a few warnings flagged by PyDev

- Unused import of urlparse
- Unnecessary definition of variable
- Incorrect indentation
Merge pull request #1479 from dpursehouse/fix-warnings

Fix a few warnings flagged by PyDev
Test cases fail when `HTTPBIN_URL` does not have trailing slash

Test cases can be run against a local httpbin server defined by
the `HTTPBIN_URL` environment variable, but it causes tests to
fail if the given URL does not end with a slash.

Ensure that the URL always ends with a slash.