Dsc 807

Hi Terence,

This request includes implementation for creating a EAD work from a selected top level work, and it also includes the changes to job edit screen for a EAD job.  The remaining workflow for EAD job (e.g. upload
a EAD file) is yet to be done as I didn't want the pull request to get too big. 

Could you please review these changes?

Thanks,

Shuang
My thought was that we are selecting a created top-level work, and attaching an EAD file to it, it's kind of a reprocessing of that work as the work is created in an previous job or process.