Upgrade clojure dependency to 1.5.1

Added profile declarations to project.clj so that you can do

    lein with-profile +1.3 $TASK
    lein with-profile +1.4 $TASK

to use an older version of Clojure.

Also modified the lein macro in build.xml so that ant can run leiningen
with arguments, like

    ant package -Dargs="with-profile 1.3"
Merge pull request #22 from stevemkim/master

Upgrade clojure dependency to 1.5.1