vec, a new Vector2 class for game development

Howdy folks.  Right after PyWeek 28, I wrote a new 2D vector class.  Just today I finally got around to publishing it.  The module is called vec, and it's up on GitHub and PyPI.

The main reason I wrote it was because all the other 2D vector classes I've seen drove me a little crazy.  I think vector objects should be immutable, like tuples.  Also I wanted to make it easier to switch back and forth between polar and cartesian coordinate systems.

vec is pure Python, so it should run everywhere your game does.  The built-in tests are still pretty rough but as far as I know the code works great.  I hope somebody finds it useful!