ISIS-1365: removes wicketstuff.version property from core/pom.xml, seemingly unused.
ISIS-1365: removes wicketstuff.version property from core/pom.xml, seemingly unused.

sanderginn/isis,apache/isis,estatio/isis,sanderginn/isis,incodehq/isis,niv0/isis,incodehq/isis,incodehq/isis,apache/isis,incodehq/isis,estatio/isis,apache/isis,oscarbou/isis,niv0/isis,estatio/isis,oscarbou/isis,estatio/isis,oscarbou/isis,oscarbou/isis,niv0/isis,sanderginn/isis,apache/isis,niv0/isis,sanderginn/isis,apache/isis,apache/isis