Avoid creation of temporary object when creating SpatiallyVaryingKernel. Fixes #124.
fix the following warning

statismo/modules/VTK/examples/vtkSpatiallyVaryingGPModelExample.cxx:93:25: warning: expression result unused [-Wunused-value]
        centerOfMass[d] * V;
Merge pull request #125 from statismo/issue_124

Avoid creation of temporary object (Fixes #124)