Screenshot: create wx app reference only when needed to avoid problems with RIDE.
Screenshot: create wx app reference only when needed to avoid problems with RIDE.

Update issue 1304
Status: Done
Fixed.

userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3,userzimmermann/robotframework-python3