Fixes & changes for #782 

Circle and Ellipse were implemented and/or documented wrong in a few places, this fixes the issues mentioned in #782.

One note is that in Ellipse width and height are still referenced as such even though they are actually the half width and half height. This is only because those properties had to exist to pass the grunt test. I will switch it to using better naming (xRadius, yRadius, halfWidth, halfHeight, etc..) if need be.

This is my first pull request so I'm still figuring out this whole process.