Update bclargs.py

> ./bclargs.py -b -s 1 -f +1+ -e 56 -j 3 -S AnimLayout -a
./bclargs.py:33: DeprecationWarning: BaseException.message has been deprecated as of Python 2.6
  raise argparse.ArgumentTypeError(e.message+message)
usage: bclargs.py [-h] [--render-anim] [--background] [--window-border]
                  [--window-borderless] [--start-console] [--no-native-pixels]
                  [--scene SCENE] [--render-frame RENDER_FRAME]
                  [--frame-start FRAME_START] [--frame-end FRAME_END]
                  [--frame-jump FRAME_JUMP]
                  [--window-geometry WINDOW_GEOMETRY WINDOW_GEOMETRY WINDOW_GEOMETRY WINDOW_GEOMETRY]
bclargs.py: error: argument --render-frame/-f: invalid literal for int() with base 10: '+1+'
        valid options are int, +int, -int


> ./bclargs.py -b -s 1 -f 1 -e 56 -j 3 -S AnimLayout -a
{'background': True,
 'frame_end': 56,
 'frame_jump': 3,
 'frame_start': 1,
 'no_native_pixels': False,
 'render_anim': True,
 'render_frame': '1',
 'scene': 'AnimLayout',
 'start_console': False,
 'window_border': False,
 'window_borderless': False,
 'window_geometry': None}