Authorization edits

General edits to Auth section pages including:

The Authentication ```<li><a``` which toc.phtml looks for is split across lines and
not found by the non-css preg selector.  
 
This section of TOC.md 
 
Authentication and Authorization
--------------------------------
 
- [Introduction](/auth/intro.md)
- [Authentication](/auth/authentication.md)
    - [HTTP Basic Auth](/auth/authentication-http-basic.md)
    - [HTTP Digest Auth](/auth/authentication-http-digest.md)
    - [OAuth2](/auth/authentication-oauth2.md)
- [Authorization](/auth/authorization.md)
- [Advanced Auth Events and Services](/auth/advanced.md)
 
should be
 
Authentication and Authorization
--------------------------------
 
- [Introduction](/auth/intro.md)
- [About Authentication](/auth/authentication-about.md)
- [HTTP Basic Authentication](/auth/authentication-http-basic.md)
- [HTTP Digest Authentication](/auth/authentication-http-digest.md)
- [OAuth2 Authentication](/auth/authentication-oauth2.md)
- [Authorization](/auth/authorization.md)
- [Advanced Auth Events and Services](/auth/advanced.md)

Nowhere else in the TOC is there a second level and this interfers with 
a more correct method of selecting the current page
 
```js
<script>
Zepto(function($) {
    $('a[href="<?= $current; ?>"]').parent('li').addClass('current').parents('ul').show();
});
</script>
 ```

This Zepto function works find in all cases except the second level 
because when their parent is selected and the 'current' class is 
added to it's li element the html > pointer style is duplicated across the second level.  This may have gone unnoticed because the Authentication link didn't change the parent li because the preg broke.

This PR also includes a change to authentication.md to about-authentication.md and each once-sub category renamed to full Authentication i.e. "OAuth2" becomes "OAuth2 Authentication"