Added private method PointVec::correctNameIDMapping().

PointVec::correctNameIDMapping() changes the _name_id_map after modifying the point set.
Merging the names of geometries together with geometric objects.
Adding tests for GEOObjects::mergeGeometries().
Merge pull request #138 from TomFischer/GeoLibII

Add merging of names to GEOObjects::mergeGeometries().