changing function name capitalization and changing log(det(X)) to logdet(X).  I didn't change the log(det()) calls involving a CholeskyDense variable because logdet isn't defined for that class, and I'm making use of the fact that for a CholeskyDense variable, det returns the determinant of the original [unfactored] matrix.
Updating readme to include the new InvertedGamma, Wishart, and InverseWishart distributions
Fixing unit tests so they pass, and replacing some matrix inversions with \ operators
Merge pull request #34 from danmerl/wishartcleanup

Cleaning up wishart pdfs