[ot][spam][crazy] Inhibition Efforts: High-Precision

[Undiscussed Horrific Abuse, One Victim of Many]

those were the first 2 categories, these are the remaining 3. i added
because the last one says there are some functions that are optimized
for extra speed.

- High-level floating-point arithmetic functions (mpf). This is the
GMP function category to use if the C type `double' doesn't give
enough precision for an application. There are about 70 functions in
this category. New projects should strongly consider using the much
more complete GMP extension library mpfr instead of mpf.
- C++ class based interface to all of the above. (The C functions and
types can of course be used directly from C++ too.)
- Low-level positive-integer, hard-to-use, very low overhead functions
are found in the mpn category. No memory management is performed; the
caller must ensure enough space is available for the results. The set
of functions is not always regular, nor is the calling interface.
These functions accept input arguments in the form of pairs consisting
of a pointer to the least significant word, and an integral size
telling how many limbs (= words) there are in that argument. The
functions in the other categories call mpn for almost all their
calculations. Of these functions about 60 are public.