added generic generator code; updated univariate and discrete
bugfix draw-bernoulli, final fixes for adding generators

added random-number-generator.lisp: base class, cl wrapper, and gsll
added GSLL dependency for call GSL's random number generators
added draw-bernoulli-bit: same as draw-bernoulli, but returns 0/1 instead of NIL/T
bugfix draw-bernoulli: return boolean for integer probabilities instead of 0,1
added tests for bugfix
added random-number-generator-tests

added tests
fixed method next for gsll-rng to return the correct type
added c program to generate lists of random chunks from GSL random number generators, these can serve as comparison to test correctness of implementation
added simple multiplicative congruential generators
added draw-binomial, draw-geometric, and draw-poisson
added Bernoulli distribution
added binomial distribution
added geometric distribution
added tests for bernoulli, binomial, and geometric distribuition
removed unnecessary comments from discrete.lisp
Merge pull request #9 from dcatteeu/master

providing random number generators and 3 discrete distributions