Use Search::Elasticsearch instead of deprecated Elasticsearch

I noticed that `Catalyst::Model::Search::ElasticSearch` uses the deprecated `Elasticsearch` module. The changes in this pull request change this to `Search::Elasticsearch`, and also enable the skipped tests again (if `ES_HOME` is set - it should point to a directory where Elasticsearch was unpacked), which have also been adapted to some API changes that came with `Search::Elasticsearch` and newer Elasticsearch versions.

These changes have been tested with `Search::Elasticsearch` 1.14 and Elasticsearch 1.3.2, using the unit tests and a small application I'm currently working on.