First major wave of PQ refactoring, including but not limited to:

* Default unit is more clearly stated in one place, not restated in many different places, and is not always the SI unit
* Converter strategy pattern in CMeasurementUnit, covering linear, affine, and different kinds of sexagesimal units
* General reorganization of CMeasurementUnit construction and CPhysicalQuantity methods, not removing any behvaiour
* Move duplicated method unitFromSymbol from derived classes into base class CMeasurementUnit
* For DBus, CPhysicalQuantity marshals both in its own unit and in the default unit

src/blackmisc/coordinatetransformation.cpp

@@ -80,7 +80,7 @@ CCoordinateEcef CCoordinateTransformation::toEcef(const CCoordinateGeodetic &geo
 
     double clambda = cos(lambdaRad);
 
-    double h = geo.height().convertedSiValueToDouble();
+    double h = geo.height().value(CLengthUnit::m());
     double x = (n + h) * cphi;
     double y = x * slambda;
     x *= clambda;