* Speedometer: Inherit from QskRangeControl
We don't need start/endAngle() etc. and value() anymore,
but can use the methods from QskRangeControl.
* Speedometer: Make it skinnable
* automotive example: Only use two specially created skins
... because the default skins do not have hints for e.g. the speedometer.
Also, display the speedometer page by default.