[racket-dev] Math library pushed

I've just made the initial commit for the math library. You will all 
notice the build time increase. Some will notice that "(require math)" 
imports a bunch of goodies that Racket didn't have before.

About half is documented so far, and half has coverage in the test 
cases. Some things are known to be broken, but not many. The most 
egregious, which needs to be fixed very soon, is this one:

   *****

   Because of recent changes to how Typed Racket deals with Any types at
   the contract boundary, typed/rackunit cannot now test higher-order
   values, such as arrays.

   *****

A practical consequence is that "math/tests/array-tests.rkt" simply 
doesn't run.

One thing I'm not sure of is whether the FFI to libmpfr works on all our 
supported platforms. Could I have all the devs run the following program 
after your next compile?

   #lang racket
   (require math/bigfloat)

   (parameterize ([bf-precision 8192])
     pi.bf)

Then reply with the last four digits printed. They should be "4888". If 
the program doesn't run because Racket can't load libmpfr, it's an 
opportunity to test the documentation. Please see if I've made the docs 
for the `math/bigfloat' module clear enough to help you fix the problem.

Thanks!

Neil ⊥