Added support for Count requests

Added count method to connection
Added Count field to response
Added test for count method

DeleteMapping implementation

Optimize API

Optimize API added:
http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/in
dices-optimize.html#indices-optimize

Support for PutMapping, Update and IndicesExist APIs

Handling errors in bulk indexing.

Fix test: replace _all index with the right index name used in test.

Support for running a _query with an http method

This allows operations like delete by query.
Included test for delete by query.

Support for passing a struct to a document instead of map[string]interface{}

Bulk witout index

Added travis-ci file

Added HTTP client override support

Added missing param to conn.Search() in example doc

Extra parameters for searching

Extra args to allow routing parameter

Aggregations support

Tests pass on 1.0