Generate new gem scaffold

...by running `bundle gem boz`.
Add minimal prototype.

- Add BDD toys.
- Add a scenario with happy path.
- Add a naive prototype w/o error checking or anything.
Refactor prototype.

- Setup RSpec.
- Move code into library and add specs.
- Change Ruby version to 1.9.3 due to issues with 1.8.7 (guard doesn't
  when files are changed, even when using a rbenv installed version).
Add TODOs.
Merge branch 'prototype'