Make URI generators REST client take a connection parameter

References #80.
Make connection an explicit mandatory first arg across the REST API client

References #80.
Cosmetics
Cosmetics
Ditto
Cosmetics
Remove clojurewerkz.elastisch.rest/connect! which is irrelevant now
Make clojurewerkz.elastisch.native functions accept connection (client) as explicit first argument

References #80.
Make native client require an explicit connection argument

References #80.
Update reference docs

References #80.
Ditto
Merge branch 'explicit-connection-argument': explicit connection is now *mandatory*