Include Wonderdog (ElasticSearch Integration) in contrib/

I propose to add Wonderdog to Pig contrib/

Wonderdog is an Apache 2.0 licensed project that adds Hadoop and Pig integration for ElasticSearch. This lets you index any Pig relation with a single UDF call, which is very powerful. Both writing searchable indexes and loading based on search queries is supported.

More information on Wonderdog is available at https://github.com/infochimps-labs/wonderdog and a great introduction to ElasticSearch is available at http://www.elasticsearchtutorial.com/elasticsearch-in-5-minutes.html

Wonderdog broke in Pig 0.10.0, and was patched to work here: https://github.com/infochimps-labs/wonderdog/pull/9 Even still, there is the issue of Pig creating schema files when storing and loading JSON that must be manually removed to make Wonderdog go.

Moving forward, I would like the Pig project to maintain Wonderdog in contrib/ and verify that it works with each version increment. Wonderdog is an incredibly useful library that is license compatible with Pig itself. Along with ElasticSearch, it adds the ability for any user to index his Pig relations and to load subsets of data by pushing search queries down to ElasticSearch.

I use Wonderdog in production and in my book, so I volunteer to do the maintenance on contrib/wonderdog.