One-time PR for Doc Reviews

@croche-okta @wdawson-okta @srinivasanagandla-okta @stsai-okta @lboyette-okta @hoanguyen-okta @karlmcguinness-okta @cwu-okta @tthompson-okta @eklein-okta

Hi team,

Since the material has been pushed to master, this pull request is a little unusual. Please add any comments to the docs here by the end of the day Monday, September 29, 2014. I will make changes and create a new branch and a new PR for the changes. Then, I will discard this PR. 

Please ping me if this doesn't work for you.

Thanks,
Evan
Note that the term "Authorization Code" is obsolete. It refers to what we now call "Session Token", but we need to be clear that this API is not centered around this notion. It is only one of many potential outputs of the API (i.e ID Tokens, assertions, other types of JWTs, etc). We just started by outputing a Session Token by default since that integrates nicely with our existing Session API. So, my recommendation is to yank the term out of this document wherever possible, and only leave it in places where we are actually talking about transitioning from this API to the Sessions API in order to get an Okta session. Unfortunately this is most noticeable in the graphics, so hopefully they are not too hard to change.