Add authentication classes to the API document

Change-Id: Ic1464f246602b809f3c29fbafd6f36b747d5d5df
Fix a couple more malformed :meth: and :class: links

Change-Id: Ie38844a40ec7a483e6ce5e56077be344242bcd99
Remove redundant sentence from quickstart introduction

Change-Id: Ic03aa394941367745f3148d299b5313849f77051
Remove empty 'internals' page

The file is empty and not linked from anywhere, resulting in
a warning when building the docs.

Change-Id: Ib995d094ef525496fe8b2a369e0a0c5b4c7bd2dd
Merge pull request #2138 from dpursehouse/more-doc-updates

More doc updates