Special characters are not escaped by search queries

[robnikkel]

The following characters are illegal in the "query" attribute for some query types (MultiMatch, Match, etc):

• - && || ! ( ) { } [ ] ^ " ~ * ? : \ /

Documentation on this found here (under reserved characters):

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html

These really should probably be escaped by this library by replacing all of these chars with a preceding slash.