Rename foo.bar example namespace to match file name

This was causing problems for vim-fireplace. It is otherwise a harmless
change.
Run prettify tests with explicit *print-right-margin*

I have that var globally rebound to `80`, for instance.
Make read-comment-header private and consolidate tests

The tests in the project are a bit messy from rapid feature development.
As we take more functions private for the next release, these will be
refactored.
Call io/file on argument to swap-in-reconstructed-ns-form

This allows users to simply pass a String when reconstructing
a file, as well as anything else with an implementation of
clojure.java.io/Coercions
Call (shutdown-agents) in slam.hound/-main

Now that swap-in-reconstructed-ns-form can be passed a simple string, we
can reserve -main for command line use only.

Closes #75