added more informative errors for non positive definite scaling for simple cases
seeded tests
fixed metrop hasings failing
added better error messages
 metropolis now uses quad potential so it gets better error checking; maybe a bad idea?
replaced DASpaceMap with a bijection object which seems a  bit simpler; test_point argument now required for Model()
added python vs C comparison for compilation
psample bug
refactored make_univariate
make_univariate -> eval univariate
remove extraneous func
call clean point from find map and approx hess
Disabling opening of a window when running example unittest.