The ..include directive isn't rendering code.

For some inexplicably reason the code blocks won't render when using the
`..include` directive. Just dump the README into the index and call it
time.
Include basic user doc with multipart encoder.
Change the code directives in the docs.
Document the user-agent constructor.
Document the SSL Adapter.
Clean up the now-overlong docs main page.
Merge pull request #7 from Lukasa/docs

Many docs updates