Successful unit test of BartProposal.draw()
successful unit test of BartProposal.logdensity()
Started working on unit tests for BartStep
successful test of BartStep.node_mu()
Successful unit test of BartTreeProposal
Added constructor for bart step test case
Fixed BartMeantParameter class to have the tree member be an instance of BartTreeParameter, cleaned up unit tests.
first test in unit test of BartStep.do_step() passed.
possibly successful unit tests for BartStep object, failures in MCMC sampler could be due to Monte Carlo issues
Merge branch 'test-treeproposal'