bug fix

Fix the bug in command line mode: AttributeError: 'VideoClipper' object has no attribute 'lang' This bug was proposed in the issue of base repository. The 'lang' attribute was added as a instance attribute of **audio_clipper** in **FunClip/funclip/launch.py**, but not a class attribute of **VideoClipper**, which further results in the missing attribute error when running in command line mode.