better errors for usability

The user experience of editing files on github and refreshing the site is pretty sharp-edged, especially for non-programmers. But Even running the site locally and knowing javascript, I often don't get a descriptive error in the terminal or browser console.

Examples:

• syntax errors in markdown and json files often cause silent failures -- would be good if the offending file could always print to browser console, better yet if the syntax error could be printed
• when adding new people to the "People" page, it is necessary to edit order.json. if there are people with md files but no entries in order.json, they don't appear on the page. If there are entries in order.json without md files, the page breaks with an inscrutable error. Ideally, the page would be robust to a mismatch or at least identify order.json as the source of the problem.

Start by reproducing the silent markdown/JSON failures locally and inspect the People page handling of order.json. Trace how files are loaded and how mismatches between people markdown files and order.json are reported in the terminal or browser console. Done means failures identify the offending file or order.json and provide a descriptive error instead of failing silently or inscrutably.