* Implemented a (mostly) comprehensive test suite for the argument parser (ab)using metaclasses to dynamically generate unit-tests for each valid argument and preset.
* Fixed failing defaults test for build_ninja.
* Added new HelpOption and IgnoreOption classes for generating tests.
* Converted default value test into individual generated tests which should give better output in case the default tests fail.
* Added a new defaults module for configurable constant values used by the argument parser to configure the default build behavior.
* Re-ordered imports in order to satisfy python linter.
* Moved the default argument application logic to the new driver_arguments module in preparation for the larger argument parsing refactor.
* Re-ordered imports in order to satisfy python linter.