Added random variate generators for the following distributions.

- RandUniform(a..b) - Uniform distribution on [,)
- RandNormal(u,s) - Normal distribution with mean , standard deviation
- RandExponential(l) - Exponential distribution with mean
- RandGamma(a) - Gamma distribution of order
- RandBeta(a,b) - Beta distribution of order and
- RandChiSquare(v) - distribution with degrees of freedom
- RandFdist(v1,v2) - F distribution with and degrees of freedom

bondaren@thsun1.jinr.ru