solve the composite MDP directly without dynamic merging

1) clean up the main model file MarkovActv.mod and fix in Bellman eqn.
2) reformat the exported .m data files
3) update the results in DATA/ (EUtil.m & jointEUtil.m)
clean up AMPL source code filenames

1) solving MDPs starts with MDP... or JointMDP...
2) estimating model parameters starts with MLE...
update source code information
re-run component and composite MDPs with beta = 0.9
blank files for dynamic programming