Added better_errors for better development.

We didn't even have worse errors.
Show people collection immediately on page load.

We previously checked in the code that makes the data available on
page load, but we forgot to check in this file that actually uses the
data.
Actually highlight people without enough Santas.

We checked in the code to figure out who needs Santas, but we
forgot the stylesheet that makes it visible.
Export CSV of song givers and their recipients.