A few improvements

  * print out reader errors and continue reading forms
  * fix bug caused by assumption that all top-level forms are
     collections (in select-ns & select-defs)
  * put docstring for functions in correct place
  * update ns form to require :refer

(note: my project that had issues with lein-gossip is a Pedestal
 project that is valid working Clojure code. Some of the forms
 were not reading properly with lein gossip.)