Volume calculations are off by factor of 2

[cbonsig]

In the 17.06 release, a symmetry factor is 16 is used in the volumetric calculations: https://github.com/confluentmedical/nitinol-design-concepts/blob/master/125-volumetric-analysis/postprocessFEA.R#L57

This assumes that FEA output represents 1/16th of the full component. In fact, the symmetry factor should by 32. The model represents 1/32nd of the full component, and a symmetry boundary condition is applied such that the model represents 1/16th only when mirrored.