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
Correct, it is an *authN* API, not a *authZ* API, so we need to keep the word "authorization" out of this document for the most part. This will evolve to cover both, once we implement OAuth, so I would be in favor of calling it the "Auth API", to be generic. Here's my suggested wording for this paragraph:
>The Okta Auth API provides operations to authenticate users, perform MFA enrollment and challenge flows, recover forgotten passwords, and unlock accounts. It can be used as a standalone API to provide the identity layer on top of your existing application, or it can be integrated with the Okta Sessions API to obtain an Okta session cookie and access apps within Okta.