level plugin by thomas <thomas@apestaart.org>

basic level indicator; prints out RMS values averaged over the buffer of
one iteration.  Insert this into an audio/raw chain.

You can plot the level envelope of the track using gnuplot, example :

tools/gstreamer-launch disksrc location=foo.wav ! parsewav ! level ! \
  fakesink silent=true > foo.level
graph -T gif foo.level > foo.gif
xview dark.gif
