Feature request: smoother linked behavior after create_nlmr_summary

[amymariemason]

from steve: "it's a bit odd that you can't just run the frac_poly_summ_mr command on an object created by create_nlmr_summary"

current reason: frac_poly_summ_mr wants the input as columns, not as a single dataframe. had setup this way as visualised multiple researchers passing csv files between steps.

plan: can we autodeduce the columns by name if dataframe with the names generated by create -> label for program

potential issues: chance of misassignment; flag to user