* Stereogrid always use Euclidean norms as weights
* DefGrad properties e1, e2, e3 (natural principal strains) added
* DefGrad properties eoct, goct (octahedral strains) added
* DefGrad from_ratios class method added
* DefGrad properties k, d, K, D (strain symmetries and intesities) added
* New class Ellipsoid added to work with ellipsoids
* FabricPLot renamed to VollmerPlot for consistency
* RamsayPlot, FlinnPlot and HsuPlot implemented
* All fabric plots have new path method accepting list of tensors