* fit_betasbp_cut.py
  - fixed 'dof' calculation with 'n-p-1'
  - fixed 'par_eps' calculation/configuration
  - added 'fit_model_bounds' using 'scipy.optimize.minimize' to
    perform function minimization with bounds
  - split the data cut section to function 'cut_data'
  - added argument 'options' to 'fit_model_bounds'
* marx_pntsrc.py
  Run MARX simulation on a given list of point sources, merge the
  output simulation results, and finally convert into FITS image.
* blanksky_add_time.py
  Add a time column for the chandra blanksky event file.
  The time data are generated with a uniform distribution
  between TSTART and TSTOP.