random variables

Hi there.

I just wanted to let you know that I implemented (some) random variables
for gnucap. essentially this is filling the stubs in func_core with the
respective gsl implementations. i put it here [1], and i consider adding
a branch to one of the repos on savannah.

this is working for vanilla gnucap, except for the build, which makes
use of gnucap-conf. see the README file for details.

have fun
felix

[1] https://github.com/gnucap/gnucap-random