Added extra info from AMv3 API details page. Fixed more markup.
Added extra info on return codes.
Added content from common concepts page of AMv3 API (these will need markup fixes, and may still need to be moved to other sections)
Reorganized call-basics and fixed some markup.
Reorganized more of call-basic. Fixed more markup.
More editing and markup fixes.
Merge pull request #4 from wvdemeer/first-draft

First draft