Use better interpolation for mobility.

[dcelisgarza]

In

EasyDD/src/segforcevec.m

Line 151 in a4ab081

bs = sum(segments(:, 3:5) .* t, 2); %bs = b.lhat --> component of screw b

there is a deconstruction of the segment's burgers vector into its edge and screw components. It is equivalent to $b_{edge}^2 = \cos^2(\theta)$ and $b_{edge}^2 = \sin^2(\theta)$, where $\theta$ is the angle between the burgers vector $\bm{b}$ and line direction $\bm{t}$.

This gives a self-consistent and crystallographically independent ratio of how screw-like or edge-like a dislocation segment is. It could be used in mobility functions to easily calculate mobilities without the need for arbitrary parameters that dictate the closeness a dislocation segment is to edge or screw types.