Molecular Closure Implementation

[tlytle1978]

I have made the changes necessary to implement the R-MMSA, R-MPY, and R-LWC closures. This did require modification of the core files PRISM.py and system.py. I also included a Picard iteration solver (solve_picard), which can be useful under certain conditions, especially when using the R-MPY closure. I have been able to replicate most of the results from "Integral equation theory of polymer blends: Numerical investigation of molecular closure approximations" by A. Yethiraj and K. Schweizer using the attached code in the .zip file.

polymer_blend_scripts.zip