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
Aha, yep, we do have `ElasticsearchError` in our own `elasticSearchFunctions` - could use or subclass that. (Subclassing might make sense, to let us catch empty search results independently of explicit "error" conditions?)