Move Hook_Rest_Data --> Controller_Rest_Data

--HG--
rename : modules/gallery/classes/Hook/Rest/Data.php => modules/gallery/classes/Controller/Rest/Data.php
rename : modules/gallery/classes/Gallery/Hook/Rest/Data.php => modules/gallery/classes/Gallery/Controller/Rest/Data.php
Fix class declarations for recently-renamed classes.
Trim no-longer-needed functions in Controller_Rest_Data.
Update Controller_Rest_Data for new REST API.
Fix bug in Response::send_file() for base64 encoding.
Merge pull request #392 from shadlaws/fixes_20130611

Fixes 20130611