Automatically segment physical members

**Is your feature request related to a problem? Please describe.**
xlFrame doesn't have the capability to support physical members that have members framing into them, without actually separating the member. Segmenting the member by hand can make it time-consuming to query the member for max/min values at the end of the process.

**Describe the solution you'd like**
I'd like the solver to scan for nodes that lie along members, segment them behind the scenes, and then (after solving) reconstitute them into their physical members for postprocessing.

**Additional context**
A technically related issue is automatically applying nodal loads to members, where the nodes are at the midspan of a member without any other members framing in at that point. Once the former task is complete, this should be trivial, if not automatic.

The issue describes changes to the solver and postprocessing, but names no files or tests. Start by locating the solver entry point and the postprocessing path, then determine how nodes lying along members are detected and represented. Done means members are segmented during solving, reconstituted afterward, and remain queryable for maximum and minimum values.

Written by the indexing model from the issue text.