Precession viewer fails to export a png file

[jglaser]

I get the following error when trying to convert reflections in an MTZ file to a png image:

$ cctbx.precession_view 7jun_-1.8.mtz labels=F-calc,PHIF-calc postscript=False output_file=7jun_-1.8.png 
Traceback (most recent call last):
  File "....../cctbx/command_line/precession_view.py", line 259, in <module>
    run(sys.argv[1:])
  File "..../cctbx/command_line/precession_view.py", line 102, in run
    print(postscript)
          ^^^^^^^^^^
UnboundLocalError: cannot access local variable 'postscript' where it is not associated with a value

The reason is a typo in the source

https://github.com/cctbx/cctbx_project/blob/157c12a0466b715053ad7d7b200756753dc11703/cctbx/command_line/precession_view.py#L101

post[s]cript

Moreover, it would be nice if the silent option could be disabled when invoked from the command line ... so as to be able to write PNG outputs