[ADD] Unit tests on the Vector class for addition and subtraction
[ADD] Unit tests on the Vector class for addition and subtraction

There are now a couple tests for the addition and subtraction operators
(+ and - respectively) to make sure that they are behaving correctly.
These tests don't look for bad inputs but just that the output is as
expected.

kmiller96/QuantumChessEngine,kmiller96/Quark-ChessEngine,kmiller96/Quark-ChessEngine