Orthotropic Plates & Quads

• Added stiffness modification factors for rectangular plate and quarilateral elements. Orthotropic in-plane behavior can now be modeled. This can be used to model the cracked stiffness of concrete and masonry for in-plane loads. Exercise caution when using this feature. These factors only apply to in-plane stiffnesses in the element's local x and y directions. Out-of-plane stiffnesses are not modified. Ensure element local axes are aligned to the directions you want to apply the stiffness modifications to.
• The arguments for many methods relating to rect plates and quads have been reorganized with the addition of the stiffness modification factors. With this update any plate/quad models you have will likely need to be updated.
• Reformulated rectangular plate element in-plane (membrane) forces. These elements are now isoparametric just like the quad elements. This was done to make them orthotropic.
• Improved docstrings for plates and quads.