Add Pry support for Pliny

As discussed in #98, let's pull Pry in instead of standard IRB. It's
very useful as a console in development and production, and also hugely
useful for debugging in development and testing. It also seems to be
fairly well standardized in that many projects want to see its
inclusion.

Fixes #98.
Pull in Shogun's prompt customization
Merge pull request #118 from interagent/brandur-pry

Add Pry support for Pliny
Drop the template's README
Add initial skeleton
Correct modules and spurious pluralization
Major overhaul
Flesh out backup source and sink
Update README
Add copyright notice
Add runner factory spec and fix issues
Test and fix ShellProcessLike logging
DRY up logging module
Clean up logging tests
Take out pointless rescue
Add PGDumpSource specs and fixes
Fix User
Fix URL handling in Gof3rSink
Take out pointless stub
Add binaries for pg_dump and friends