Merge pull request #21 from fredericksgary/master

Add update
Fix reflection warning / bad assert
Test on 1.6.0 and drop explicit Clojure dependency
lein-release plugin: preparing 0.2.2 release
lein-release plugin: bumped version from 0.2.2 to 0.2.3-SNAPSHOT for next development cycle
Merge branch 'master' of github.com:Prismatic/plumbing
Update README to point to latest version