Switch to diagnosis date for patient profile

Used to be diagnosis year, not precise enough (esp. for small children).
Switch to plain text input for date fields

Chrome rendering of `<input type="date">` was confusing more than
practical.
Add better error message if app failed to compile
Remove dead code in simple form component
Add note in README on installing new vendor package
Merge branch 'master' into jebeck/improve-two-week-view