Sat Dec 28 16:34:02 EST 2013

Float vectors

It seems that variable-size arrays are problematic due to the need to
define a C type for each array size.  Is this so?  Yes, but doesn't
look problematic: all just functions / no macros.

It seems simplest to work like this:
- once size is known => (define f10 (make-array-type float 10))
- allocate memory using (malloc f10)

Actually what is needed is ffi/vector and `make-f32vector`