Remove default Content-Length from GET requests.

Fix #1051.
Fix python 2.6 unittest compatability issue.
Add myself to AUTHORS.
Always add Content-Length to HTTP PATCH.
Remove Content-Length from GET/HEAD by default.

Now, Content-Length is only auto-added for non-GET/HEAD requests.
Merge pull request #1142 from theaeolianmachine/removeGETContentLength

Remove default Content-Length from GET requests.