A top-level vcproj (really a .sln file) only makes sense when sub-
projects are generated too, since the solutions generator will ignore
all non-generated projects.

Originally-by: Marius Storm-Olsen <marius.storm-olsen@nokia.com>
Change-Id: Iff09279d5760b5114a4cfb9b58ad677f2f69fa58
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>