Add Fressian ReadHandler for set

By default Fressian converts sets into java.util.HashSets
This is problematic in Clojure 1.6 as it has changed equality
for persistent collections containing Java collections.
Add HTTP endpoint /id for flake id's

Resolves #108
Merge pull request #114 from danielcompton/add-read-handlers

Add Fressian ReadHandler for set
Merge pull request #116 from danielcompton/flaky-http

Add HTTP endpoint /id for flake id's
Upgrade all dependencies except Clojure
Upgrade Clojure to 1.6