ChartClass 0.4 added

Actually version 0.4.3 to be clear.

There's a lot of extra information that can be used now:
- title of the graph
- subtitle of the graph
- title of the Y-axis
- adapt to negative values (min and max to be given)
- vertical grid lines added
- zero-line adjusted away from vertical center depending on min/max values
https://sourceforge.net/p/chartsclass/screenshot/ChartClass.png

The interface is adjusted accordingly, with a lot of options for the graph:
- show title
- show values
- show axis title
- show axis legend
and the possibility to toggle them all.

The generation of negative numbers can be set on/off.