Resolution for Issue #390.
Reuse the docstrings from the classes in tensorflow.contrib.distributions as docstrings for the RandomVariable classes in Edward. Now calling help() on a RandomVariable class will show information about the distribution and the required parameters.
add docstrings to random variables
nice implementation! i hadn't thought of using type() here. could you add a unit test for one distribution, say, Bernoulli or Normal? for example, you can just check if the string Bernoulli.__doc__ is non-empty.
unit tests for randomvariable docstrings