Removed deprecation warning (was using joda DateMidnight)
(cherry picked from commit 55df020)
Timestamping of participations to discover late signups
(cherry picked from commit e79959e)
Using a popover to explain warning icon for late signups
(cherry picked from commit eda15cc)
Improved Excel export: column to indicate Guest + column with late sign up time
(cherry picked from commit 2ff9b31)
Cleaning up sloppiness: added icon file to GIT, removed dead code
(cherry picked from commit 628994c)