PyPlot demo

PyPlot-Demo (3.4 MB, 4:30) http://stef.mientki.googlepages.com/pyLab_works_demo_pyplot.html, Showing sine / square generator with a realtime XT-plot based on a slightly modified PyPlot.
Demonstrates how signals can be extended with extra features, in this case: signal color, line width and signal name.
Probably PyPlot is too slow for fast realtime signals, so we'll also implement ScopePlot and for even more beautiful pictures we'll introduce MatPlot.