[racket] Thanks for Math

Thanks for the math library. I started using some of the linear algebra functions for my paid programming, and have had zero trouble with any of it. Matrix-solve works like a dream, and the docs are on the mark.

I have to wonder what would happen if a program manager were looking over my shoulder on the rare occasion that I commit a Contract Violation for issues like non-invertible matrices. PMs are a humorous lot in regards to violation of contractual terms. 

rac