Mpdreamz/NEST — pull request #392 by jjherbst (2013-11-19 20:02:13+00:00)
Title: Added both the Preferred and Custom preference

Added the rest of the preferences currently supported by ElasticSearch.
1. Custom
2. PreferNode (_prefer_node:xyz)

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-request-preference.html