Bugfix (aka accidentally a tuple):

    * _transpose_environ treated base_url as a string when it was a tuple.
      By accident, len('/static/') - 1 == len(base_url) + 1 == 7. Breaks for a
      url of any other length.
Bugfix MediaCling debug_cling attribute.

MediaCling's method declaration of debug_cling was insufficient to override the
instance attribute of the same name.  Replaced with explicit declaration.
Merge pull request #7 from axelmagn/master

Bugfix Cling._transpose_environ and MediaCling.debug_cling