use longs for the "limbs" of bigints. However, when GMP's configure script
detects that mingw64 is compiling, it defines LONG_LONG_LIMB, which makes the
type of limbs long long, or 64 bits. This is fine; a 64-bit machine should use
64-bit ints for the digits of its bigints. It would have been nice to know
this special case earlier, though I can see why it's not advertised: most
users don't need to know, and it seems like it's obviously the right choice to
make when dealing with Win64's annoying ABI.
Made "mpfr.rkt" search for 'mpfr_set_z_exp if 'mpfr_set_z_2exp isn't found.
Hopefully this allows the bigfloat tests to finish on DrDr. If not, DrDr
will need a libmpfr upgrade.
Made some minor doc fixups
Cleaned up other docs in preparation for alpha-testing announcement
Created `math/utils' module for stuff that doesn't go anywhere else (e.g.
FFT scaling convention, max-math-threads parameters)
Reduced the number of macros that expand to applications of `array-map'
Added `flvector-sum', defined `flsum' in terms of it
Reduced the number of pointwise `flvector', `flarray' and `fcarray' operations
Reworked `inline-build-flvector' and `inline-flvector-map' to be faster and
expand to less code in both typed and untyped Racket
Redefined conversions like `list->flvector' in terms of for loops (can do
it now that TR has working `for/flvector:', etc.)
Fixed a few limit cases in some distributions (e.g. (uniform-dist 0 0) didn't
act like a delta distribution, (beta-dist 0 0) and (beta-dist +inf.0 +inf.0)
pretended to be defined by unique limits even though they can't be)
Made integer distributions' pdfs return +nan.0 when given non-integers
Added "private/statistics/counting.rkt", for hashing and binning samples
Added `flvector-sums' (cumulative sums with single rounding error)
Added `flinteger?', `flnan?' and `flrational?', which are faster than their
non-flonum counterparts (at least in Typed Racket; haven't tested untyped)
