Move Hook_Rest_Tag --> Controller_Rest_Tag.

--HG--
rename : modules/tag/classes/Hook/Rest/Tag.php => modules/tag/classes/Controller/Rest/Tag.php
rename : modules/tag/classes/Tag/Hook/Rest/Tag.php => modules/tag/classes/Tag/Controller/Rest/Tag.php
Fix class declarations for just-renamed files.
Rewrite Controller_Rest_Tag.
Move Hook_Rest_Tags --> Controller_Rest_Tags.

--HG--
rename : modules/tag/classes/Hook/Rest/Tags.php => modules/tag/classes/Controller/Rest/Tags.php
rename : modules/tag/classes/Tag/Hook/Rest/Tags.php => modules/tag/classes/Tag/Controller/Rest/Tags.php
Fix class declarations for just-renamed files.
Change how Controller_Rest::action_post() handles new vs. existing resources.
Rewrite Controller_Rest_Tags.
Merge pull request #400 from shadlaws/fixes_20130612_2

Fixes 20130612 2