Default screen name maker break with some processes

[nolanbconaway]

Sometimes jarjar makes invalid screen names:

$ jarjar './go.sh'
Creating screen: `./go.sh`.
Cannot identify account '.'.
Traceback (most recent call last):
  File "/usr/local/bin/jarjar", line 366, in <module>
    main()
  File "/usr/local/bin/jarjar", line 326, in main
    screen.send_commands('unset HISTFILE;')
  File "/usr/local/lib/python3.7/site-packages/jarjar/screen.py", line 116, in send_commands
    self._check_exists()
  File "/usr/local/lib/python3.7/site-packages/jarjar/screen.py", line 145, in _check_exists
    raise ScreenNotFoundError(message, self.name)
jarjar.screen.ScreenNotFoundError: Error code: 404. Screen "./go.sh" not found

We should find out which characters are invalid in screen names and filter them out when making names.