This distribution re-implements some, but not all, of the formulas
that come with GIS::Distance in the C programming language. C code
is generally much faster than the perl equivilent.
In most of my testing Ive found that the C version of the formulas
outperform the Perl equivelent by at least 2x.
This module need not be used directly. GIS::Distance will automatically
use the ::Fast formulas when they are available.