Fix for Bug#99

1. The IFA014 NsVirtualLinkDesc IE contains a ‘provider’ and a ‘version’ properties. The reason for those properties is totally unclear, since the NsVirtualLinkDesc is part of the NSD and it is written by the same service provider as the NSD. Probably originally there were some intentions of having the NsVirtualLinkDesc as an independent object from the NSD. But that never materialized.

2. Likewise the NsVirtualLinkDesc IE contains securityParameters defined as the signature of the descriptor together with the signing certificate and the algorithm. Likewise the NsVirtualLinkDesc IE contains securityParameters defined as the signature of the descriptor together with the signing certificate and the algorithm.