Pupil Mask Flag for WFRIST

[robelgeda]

This is a response to #182. This functionality is available in the current version. This PR introduces functions and parameters to toggle pupil masks.

New:

• Parameter: set_pupil_mask_on

  • WFI.__init__: bool
  • Set pupil mask on/off (True/False).
  • To use default settings, set set_pupil_mask_on to None.

• WFI class functions

  • toggle_pupil_mask(set_pupil_mask_on)
    • set_pupil_mask_on: bool or None

auto_pupil is set to False if the user chooses a custom pupil. This can be undone by toggle_pupil_mask(None).