Added options to alias creation

Hi Ruflin,
 I'm trying to implement the alias API as is described in 

 http://www.elasticsearch.org/guide/reference/api/admin-indices-aliases.html.

 This is my first approach. With this we have functionallity to make filtered aliases and add routing in alias creation (for searching and indexing)
  I can't find a solution for the Elastica_Exception_NotImplemented part, but we can make a filtered alias passing the filter as a string