Slender wall design

First I just want to say I am very impressed with this project! I too have been writing/developing an FEA package currently as well. My primary use case is for doing tilt up/slender wall panel analysis design. After finding your project I am considering now just forking/contributing here. The main things that I see that would still need to be implemented are:

1) Support for self-weight of the finite elements. I could have missed this but I don't see any density functions etc.

2) Extend the meshing routines to support quad/rect FE generations with voids/openings

3) Support for Cracked sections/moment of inertias. Most of the design codes require assuming a fully cracked section. Therefore I think I would need to add a few new variables to allow some sort of coefficients to reduce the gross moment of inertia based purely off the section geometry.

4) Composite Sections? The cracked moment of inertia is a function of reinforcement and axial load at the section. So I suppose I may also want to add support for maybe a "Reinforced Concrete" material and add some logic to modify the stiffness matrix based on this.

5) Easy way to add line loads + eccentricity to the meshed structure and convert these to lumped nodal loads/moments at the individual FE plates.

6) Second order analysis for geometric stiffness to handle the P-delta contribution to ultimate load moments.

I am pretty sure I know how I would code most of these as for implementation but I am curious of your inputs if you have already implemented any of the above and I missed it. Or if you have any thoughts or see any fundamental issues to implementing these.

Again great work and I wish I had found your library sooner!