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
Yeah, I'd love to make improvements to this, but I don't want to spend too much time on it when this code may be replaced in the medium-to-long term.