Adding a New Unit Type

If you are interested in adding a new unit type (dimension) or a new unit for a given dimension, follow these steps:

1. For a new unit type, create a new entry in the UnitType enum in units.py

2. For a new unit type, create a new derived class that inherits BaseValueWithUnit, mimicking patterns as needed

3. For just a new unit within a given type, just add a new ID to the unit type class, and update the unit string/id/convert functions accordingly