Migrate to Elasticsearch 1.x

This migrates Archivematica to Elasticsearch 1.x (tested with 1.3.4), and the official Elasticsearch Python library instead of pyes.

Known issues:

* [x] Number of files in an AIP does not display correctly in the advanced search view
Okay, removed the comment. Since pyes has both a "raw" search and a more pythonic version, I wasn't sure if this was meant to be some kind of alternate wrapper to the raw search. Makes sense in that context.