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
The third argument is (probably) not really needed in this version, but I always feel bad about changing function signatures in an incompatible way. That said, it's only used within this one file...