make it table-driven and have it cache the immutable values from
QLibraryInfo.

Change-Id: I07ed89152aa964bc9edf4436ee7c42f99cc6bcd3
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>
Reviewed-by: Marius Storm-Olsen <marius.storm-olsen@nokia.com>