Add object orientation to the physics library
Add default arguments to Vector

If constructed without arguments, physics.Vector is a zero-vector.
Change exception name to DimensionalityError
Fix 3-Vector instantiation issue
Robustify and add scalar operations to vectors
Require that Vector components be float()able
Solve compatibility issues between physics engines
Merge pull request #4 from umbc-hackafe/f.oo-physics

Rewrite physics engine