Handle ElasticSearch character escaping
Prevent HTML escaping of '
to "
in ESQuerySet templates and add a character escaping function.
See https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html#_reserved_characters
Not all cases are handled: searching for Brinkley\'s
brings back a strange behavior (searches for Brinkley
or s
)