Uuids::Base module added [passes]

== Addons

* Uuids::Base module. When the module included to ActiveRecord model, it declares required #uuids attribute.
* dummy Item model for testing Uuids::Base.

== Changes

* README.rdoc - Uuids::Base usage documented. Some errors already fixed.
* coveralls included to the `rake full` task.
* version changed to 0.2.0 to reflect new Uuids::Base feature.