Moving MiniTests and Arranging Modules

- moving MiniTest tests out of files in /lib and into their own respective testing
  files in /test, including:
    * Attribute Methods
    * Conversion
    * Dirty
    * Naming
    * Validations

- for the above files, the addition of an initialzation method in Person takes care
  of including example modules contructed. This was a way of including the modules
  upon initialization of the Person instance in the tests, as extending the modules
  after initialization was not giving the desired functionality

- adding line of code to require all files in /lib directory. Although, one most runs
  of the test suite, all files are not being loaded correctly, resulting in failed or
  errored tests
Tests for All Modules

- Re-arranging test names for Attributes Methods, Conversion, Dirty, Naming, Person and
  Validations

- Pulling tests into their own files for ActiveModel::Model, ActiveModel::Serialization,
  ActiveModel::Serializers::JSON and ActiveModel::Serializers::Xml
Converting Classes to Modules and Removing Tests

- converting classes into modules to be included in classes and instances of classes in tests

- removing MiniTest code, which was moved into their own test files