Update schedule with latest discussion

Tighten the wording of the day 1 schedule, and hedge a little more on
the exact time stamps.

Include some time after each break-out session for sharing with the
whole group on day 2.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Change-Id: I950eb05ef9f094c67304bfa497669d523b97047a