Fixed the Quadratic Bezier curve.  Current code made implemented it as a Cubic Bezier with the second and third control points equal to the second Quadratic control point.  This is incorrect (see: http://fontforge.sourceforge.net/bezier.html).

* Updated QuadraticBezier class to not inherit from CubicBezier.  Implemented required methods.
* Implemented QuadraticBezier.length() to mathematically find the curve length, instead of approximating it.
* Updated tests for QuadraticBezier.point().  Previous points were calculated using a CubicBezier with the incorrect control points.
* Added test for QuadraticBezier.length().  Tests against the length found from approximation using an equivalent cubic bezier curve.
Changed URL.
Merge pull request #10 from justingruenberg/quadratic-length

QuadraticBezier is incorrect