* separator can cause issue when sending data (WebService, FSD)
* re-parsing (print and parse again) can cause to undesired results as the separator is mistaken as decimal separator with a different locale
* separator now a parameter so it can still be used
This fixes the GCC warning "deleting polymorphic object with non-virtual destructor".
They are marked final so the virtual dispatch can be optimized out, because they don't need to be overridden.
* All members of CMeasurementUnit moved into nested pimpl class Data.
* CMeasurementUnit has only one member: a pointer to a const Data.
* Static const CMeasurementUnits replaced with static const Datas.
* Each CMeasurementUnit singleton method returns by-value a CMeasurementUnit containing a pointer to a static const Data.
* Means CMeasurementUnit is trivial to copy because we never copy the pimpl members.
** Works because the available units are fixed at compile time so we never need to create novel units at runtime.
* CMeasurementUnit and every one of its members is a literal type.
** This requires using QLatin1String instead of QString.
* Every static const CMeasurementUnit is static constexpr.
** This means they are initialized at compile time, no runtime initialization needed.
The following issues were fixed
* Fixed wrong/missing namespaces
* Fixed obvious typos in documentation
* Documentation not in sync with source code
refs #544
