Add Gear Ratio related functions in multiple areas

.. RideFile - add rounding approach for gear values (different rounding depending on value) - leading to discrete GearRatio values 
.. AllPlot - exclude Gear Ratio from Smoothing (to keep the discrete value) - and change curve type to "Steps"
.. ScatterPlot - specific handling for GearRatio since values between 0.01 and 1 are relevant for GearRatio and must not be filtered out
.. RideFileChache - add Distribution Data for Gear Ratio and fix Distribution Cache for DataSeries with > 0 decimalsFor
.. Histogram - add GearRatio to Histograms (both Rides and Trends)