Revise chart color scheme algorithm

Initial situation:
--------------------------------------------------------------
Charts provide color schemes to differentiate between sections.
--------------------------------------------------------------

Actual behavior:
--------------------------------------------------------------
The color scheme algorithm generates unique colors for each chart segment based on an initial color scaling in color intensity.
At some point it might be difficult to differentiate among lots of chart segments.
--------------------------------------------------------------

Expected behaviour:
--------------------------------------------------------------
The color schemes intensity should always be sufficient to differantiate between chart segments.
--------------------------------------------------------------

Comment:
--------------------------------------------------------------
Consider "RandomColorScheme"
--------------------------------------------------------------