[simplify interface] closer integration between run_scm and run_scm_collect

[dfalster]

Currently we have run_scm, run_scm_collect, run_scm_error and build_schedule.

There's considerable duplication and it's frankly confusing. Suggest combining, make collect, refine_schedule arguments in run_plant instead of different functions?

Additionally, As per #206, suggest renaming to run_patch, run_plant? Actually, how about solve_system. The stochastic version could then be stimulate_system