add a comment about the performance hit caused by adding a timeout
start app repl in 'user and provide a useful welcome

closes #159
fix applicaiton typos
Merge pull request #160 from pedestal/repl-options

start app repl in 'user and provide a useful welcome
Replaced clojure.data.json with Cheshire

Exposes Cheshire BigDecimal, key-fn and array-coerce-fn options as
body-params parser-map options hash-map.