Drop tests against 1.3 and 1.4
Drop tests against 1.3 and 1.4

I encountered the following bug in Clojure 1.3 and 1.4:

http://dev.clojure.org/jira/browse/CLJ-757

There's not much sense in testing against really old versions of Clojure
if their transients are broken.

rschmitt/collider,rschmitt/collider