Extract tests from source directory.

Separate mock library from source.

Demonstrate on-the-fly flip for sprites.

Some contents for deliberation.

Remove symlinks and make codebase use common modules instead.

Add tests for initialization and teardown for all input methods.

Add memory and data-related implementations for handling game data.

Correctly dereference pointers.

Use short names for int types.

Ensure each initialization method is in its own source.

Add geometry methods for point, vector, and rectangle.