BasePK javadoc update
Some fixes to Unit testing to use assertThat. Along with some other logic for starting UnitSystem things
Some UnitSystem stuff
Added a fix for the signs when reducing a Fraction Pair so that the sign is only displayed with the first item
Added more unit tests for UnitMeasurement and UnitSystem.
Added more tests for converting units.
Reordered and fixed getBaseUnit so that it is Weight, then Distance, then Volume and that the base unit for pound and ounce is Pound. Also added more tests
Adding the rest of the convertToBase tests
Got all imperial and metric tests to pass for now. More test time
More tests for converting imperial units. The tests pass for a base unit to any, but not volumne unit to volume unit