smooth-dl.py: fix some pep8 issue

  smooth-dl.py:38:1: E402 module level import not at top of file
  smooth-dl.py:39:1: E402 module level import not at top of file
  smooth-dl.py:40:1: E402 module level import not at top of file
  smooth-dl.py:41:1: E402 module level import not at top of file
  smooth-dl.py:42:1: E402 module level import not at top of file
  smooth-dl.py:43:1: E402 module level import not at top of file
  smooth-dl.py:44:1: E402 module level import not at top of file
  smooth-dl.py:45:1: E402 module level import not at top of file
  smooth-dl.py:46:1: E402 module level import not at top of file
  smooth-dl.py:57:5: E265 block comment should start with '# '
  smooth-dl.py:96:1: E302 expected 2 blank lines, found 1
  smooth-dl.py:111:1: E302 expected 2 blank lines, found 1
  smooth-dl.py:173:25: E128 continuation line under-indented for visual indent
  smooth-dl.py:195:80: E501 line too long (84 > 79 characters)
  smooth-dl.py:246:9: E128 continuation line under-indented for visual indent
  smooth-dl.py:248:24: E711 comparison to None should be 'if cond is None:'
  smooth-dl.py:320:13: E127 continuation line over-indented for visual indent
  smooth-dl.py:333:9: E128 continuation line under-indented for visual indent
  smooth-dl.py:334:9: E128 continuation line under-indented for visual indent
  smooth-dl.py:335:9: E128 continuation line under-indented for visual indent
  smooth-dl.py:336:9: E128 continuation line under-indented for visual indent
  smooth-dl.py:338:23: E711 comparison to None should be 'if cond is None:'
  smooth-dl.py:343:21: E128 continuation line under-indented for visual indent
  smooth-dl.py:345:21: E128 continuation line under-indented for visual indent
  smooth-dl.py:351:17: E128 continuation line under-indented for visual indent
  smooth-dl.py:353:17: E128 continuation line under-indented for visual indent
  smooth-dl.py:355:9: E265 block comment should start with '# '
  smooth-dl.py:358:17: E128 continuation line under-indented for visual indent
  smooth-dl.py:363:23: E128 continuation line under-indented for visual indent
  smooth-dl.py:364:23: E128 continuation line under-indented for visual indent
  smooth-dl.py:374:13: E128 continuation line under-indented for visual indent
  smooth-dl.py:426:17: E128 continuation line under-indented for visual indent
  smooth-dl.py:427:17: E128 continuation line under-indented for visual indent
  smooth-dl.py:437:13: E128 continuation line under-indented for visual indent
  smooth-dl.py:438:13: E128 continuation line under-indented for visual indent
  smooth-dl.py:439:13: E128 continuation line under-indented for visual indent