check property declarations of overridden properties

Now it's an error to pass nonsense like project.blubb:1
on the command line.

Task-number: QBS-431
Change-Id: I1e2128bce953b7acef4abe0fd09808ba1f71d1f9
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
yield error if Product.name conflicts with a module name

Change-Id: Ia06fdf283b74d3d1b5418d1752a0fa717fca08d4
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>