math module for Decimals

[jerry.carl.mi at gmail.com]

> Which math functions? ln, log10, exp, sqrt already exist as methods of  
> Decimal instances. At the end of the Decimal docs there are a few  
> examples, including computing sin and cos (but apparently they naïvely use  
> a McLaurin series like you noticed in other module).

Hi Gabriel - thanks! For example all goniometric functions are
missing. Or the log(x, base). Or rand(). Sure I can spend time trying
to put it all together but I thought somebody would have done that
already. It seems though that the codes that are out there are not
ready - every one of the modules i mentioned above has some issues.
Maybe I can put bits and pieces together, but if anyone knows of a
well proven module (as is), I would feel much safer using that (again
I am not a mathematician and poking into these algorithms makes me
feel like trying to fix an automatic transmission).