Python script for proofreading CSV files

Since we're doing a lot of entry by hand and column headers have a habit of changing around, I figured it'd be nice to be able to catch typos and standardize on column headers and variable names. `proofread.py` checks for extra whitespace and known vs. unknown field names. It's caught a few misspellings for me already!

I put some usage examples in there for files that are currently a little off so you can check it out (although I'm sure there're more fields that need to be added to the canonical lists).