[phobos] Adding to std.mathspecial

[Christopher Louden]

Hello,

The documentation for std.mathspecial indicates that the module is 
incomplete.  Are there current plans to add more functions to this module?

I am currently working on implementing some statistical calculations in 
D that require the use of hypergeometric functions.  I am converting the 
code for these functions from the Cephes C library and can add them to 
the module if desired.

Chris