CORE-6133 allow entity-type of empty string to be nil
updated clj-icat-direct dependencies

clojure -> 1.6.0
korma -> 0.4.0
CORE-6133 Added entity-type parameter support to data-info

The directory listing endpoint, /entries/path/zone/*, now supports the entity-type parameter.
fixed arg order issue with invalid-argument trap
CORE-6133 paged directory listing supports entity-type