Write skeleton of how the library will be structured

* Properties and validators will exist in their own modules
* Explain what Schema base class is responsible for.
Renamed file and autoload ObjectSchemas::Schema file.
Make ObjectSchemas::Schema an abstract class

* Only subclasses can be created.
Setup testing framework and wrote first test

* using Minitest::Spec, colorizing using minitest/pride
* attempt to autoload the common debugger libraries
* include the `./lib` directory in the test_helper so individual tests
  can be run using `ruby path/to/test`