Merge pull request #2 from livingsocial/rspec-helpers

Add RSpec matcher, shared context for more immersive roleplaying
Document RSpec usage
Prep for version update and 1st rubygems release
Add spec for failure message of custom matcher
Extract custom matcher into a proper object...

...and patch it into RSpec using the mechanism suggested in the RSpec docs
Move classes used in testing into their own namespace, file

Who knows?  Someone might want to define Agriculture::Animals::Yak some day!
reword specs
Rearrange namespace for test integration
Add Test::Unit integration, with (of course) tests