Added left() and right() methods and free functions to Vector2D.
left() transforms <x, y> into <-y, x>
right() transforms <x, y > into <y, -x>

Added unit tests for left() and right()

Added BS_BUILD_DEBUG to debug builds of the UnitTests Visual Studio project
Merge branch 'master' of https://github.com/theJ8910/Brimstone