some documentation and spec tests

and the gems to go along with them

- yard
    - redcarpet
- guard
    - guard-rspec
add simplecov, update README, continue to test

main focus right now is improving test and documentation coverage.
simplecov will generate coverage reports on every `rake spec`. I'm
attempting more or less complete coverage before I move forward.
Specifically, I know I need to deal with the objects returned by
`HieraController#lookup` and friends (`#lookup_additive`, `#get_all`,
etc) because they are actually quite ugly. The main issue there is that
my tests don't really cover the UI, although it may be as simple as
updating my cucumber tests? I'm not 100% sure yet.
add inch-ci.org badge
100% hiera_controller test coverage
Pull Node class methods into a new class YamlDir

also fix tests, update UI
major refactor as part of spec testing

- create ParameterCollection and Parameter classes
    - lots of really basic work, hopefully not for naught
    - I may not yet be using Parameters everywhere it would be useful
- rename a bunch of things
- pull out YamlDir into its own file and improve tests
slight changes to Node and Parameter