0.3.2

Improvements:
-Slightly optimized Plt_tecto_Mars
-Vectorized and optimized parts of SH_deriv_store, resulting in a significant speedup of at least x6.

Modifications:
-Displacement_strains now outputs the total strains together with the extensional and flexural strains.

Corrections
-Slightly corrected how the extensional strains are estimated at the surface in Displacement_strains following Beuthe (2008). Previously multiplied by Te / 2, now multiplied by Te / 2 / (1 + Te/2/R) ~ Te / 2 (for large R). This is going to matter mostly for small bodies.