[issue #43] changed the quality class calculation according to new rules
[issue #43] adaption to the new rating rules
[issue #43] introduced getQualityClass in CalcCache that is now used in every place where the quality class has to be available, replaced quality class legend according to new calculation, introduced point cap at 5.0 as more points shall not be possible (do not make sense)
Merge branch 'feature/43-fgsk-rating-optimisation' into dev