( ) Make KPropertyUnit public because user needs conversion functions for units.
(*) Or remove conversion to points in KProperty and KReport so user won't care.
In the 1st case what's with KReportUnit? -- remove and reuse KPropertyUnit in KReport?
In the 2nd case - incompatible change compared to 3.0.
[ ] Fix rounding errors and precision in the parents of composed propert (QSizeF on the screenshot):