Changes in version 0.2.0                        

  - Improvements to the tmle3_Update class.
  - Changes to the Spec object for stratified TMLEs.
  - Adds cursory support for MSMs (still WIP).
  - Changes to handling for censored outcomes, including addition of
    inverse probability of censoring weights.
  - Proper handling of survival outcomes subject to right-censoring in
    point treatment settings.