Analytic tests

The analytic formulas exist, as much as possible, and are used in plot.densities and plot.moments, which are the new names for the correctness tests after I gutted and fixed everything I did wrong the first time I designed it. The only problem is that the t-distribution part is buggy. I probably just typed the parameters in wrong (in NIW.marginals), or maybe the dt.density function is broken. I dunno because I haven't actually run it indepently of the whole framework.

What a jerk this was.

I'm going to sleep for 4 hours, then give you a ring, eh? We need to write the report quickfast, and finish the Rdocs. I'm going to prioritize that when I wake up. If there's time left over, I want to tweak rNIW so that it doesn't duplicate rMNIW.