Add PipeOutput class

  - Add pipe output class, and refactor it and the SerialOutput
     to have a common superclass as they both perform the
     conversion logic

  - Add sample config stanza for the PipeOutput

  - Add an initial checkin of the FloorSimulator code

  - Add a method to the layout to determine the correct order to
     output the pixels for the dancefloor
Added --playlist option, and configurable plugins

  - A playlist can now be passed in on the command line using
     the --playlist argument.

  - A playlist is a yaml file consisting of a list of plugins
     in the playlist, and any configuration options for them.
     All plugins support the duration: attribute, and it is
     a time given in seconds

  - Sample playlist, playlist.yaml included

  - VisualistionPlugin configure method changed to take a
     'config' argument which is a dict of options passed in.
     It is up to the plugin to decide what to do with them.