Always send headers via the server handler

Fixes #293

git-svn-id: http://gsoc.svn.wordpress.org/2013/rmccue/trunk@2287 f69abe3c-2ee2-4550-9a6d-17bd458115be
Use the correct method for thumbnail data

git-svn-id: http://gsoc.svn.wordpress.org/2013/rmccue/trunk@2288 f69abe3c-2ee2-4550-9a6d-17bd458115be