Fix missing ----

My previous commit removed this.
Cleanup FAQ
Cleanup note on hmac-sha256 in Advanced Usage
Cleanup short statement in Advanced Usage
Cleanup another note in core lib advanced usage
Vague section.

I don't have the knowledge to improve this part. I cleaned up the
language, but I'm not actually sure what's going on here.
Cleanup section in Core library
Clean section in 'how to use it?'
How to use it -> Usage
Cleanup introduction in Access Rules System
How to use -> usage
Usage section: Cleanup first paragraph
Generic authorization: uathorized -> unauthorized
Authorization: insert 'an'
Session: rephrase first paragraph
Remove ++++...
FAQ: authentencation -> authentication
Rephrase reject handler sentence
Merge pull request #8 from johnwalker/doc

Doc cleanup #2