Persist hosts throughout tests

The spec helper initializes hosts before the test suite is begun. The
hosts array is assigned to an RSpec setting to persist access across
testing.
fixup based upon review comments

- moved around the code so that the helpers are accessible from the lib
  dir
- created beaker-rspec.rb that pulls in all necessary files to run tests
Merge pull request #1 from anodelman/hunner

Persist hosts throughout tests