Resolve path of relative plugin directories relative to root
Resolve path of relative plugin directories relative to root

  - Change the way the plugin directories are resolved,
     instead of being relative to the current working
     directory they are now relative to the root of
     the main DDRPi script, meaning that it can be invoked
     from anywhere, no longer just in the root directory

fraz3alpha/DDRPi,fraz3alpha/led-disco-dancefloor