Making cli53 importable as python module
Adding support for pluggable route53 connection

Allow 3rd party libs calling commands with suppling their own route53
connection.
Merge commit 'refs/pull/86/head' of github.com:barnybug/cli53

* github.com:barnybug/cli53:
  Adding support for pluggable route53 connection
  Making cli53 importable as python module