Issue 4044: Search overhaul, part 1

Issue 4044: Search overhaul, part 1

This is just the json generation and indexing bits to send data to the new Elasticsearch cluster, with rake tasks to do a full reindex. We still need to hook it into the callbacks -> redis buffer cycle and create the new search classes. 

https://code.google.com/p/otwarchive/issues/detail?id=4044
If multi-language series are likely, I suppose it would be possible to return some agreed value if more than one language is present. But if this is a feature that is seriously going to be used and extrapolated from the works, you'd probably need to look through all the works to make sure they were the same before returning a value, rather than just the first one. But maybe later... :)