added ccdf_log for pareto distr
added ccdf_log to scaled_inv_chi_square distr
added ccdf_log to skew_normal distr
added ccdf_log to student_t distr
added ccdf_log to uniform distr
added ccdf_log to weibull distr
added ccdf_log to bernoulli distr
added ccdf_log to beta_binomial distr
added ccdf_log to binomial distr
added ccdf_log to neg_binomial distr
added ccdf_log to poisson distr
added ccdf_log to function signatures for all distributions
added ccdf_log functions to manual