Add plupload
Implement drag and drop via plupload

* remove old code
* use drag and drop
* add/alter required markup
Add the page as a savvy global

So that required assets can be added on the fly
Fix display of upload
Implement chunked uploading

Current html5 drag and drop of large files ~800mb crashes some browsers (chrome).  Chunking fixes that problem, but makes it a little more complicated.

This is a basic implementation following https://github.com/moxiecode/plupload/blob/master/examples/upload.php as an example.

A better solution would be to save each chunked file individually and then recombine them once the last chunk has been saved.  This would allow for better error correction and re-sending of chunks.  That is another step however. :)
Change structure of manager templates to support other formats
Add json output for file uploads

This removes the need for a cumbersome `barebones` format and should allow for better communication with plupload for errors.