Added kv_map_name.

Removed mutli_field from kv_map.

Changed k=v separator to avoid the tokenizer.

Splitting the name from the uid in the kv_map allows for easier searches (no need to wildcard over uids you may not know) and would make this easier to multi_fields with a custom tokenizer to make direct key or value matches. This was done so that faceting on kv_map/kv_map_name returned useful results when scoring k=v.