Change match list to be a list rather than a dict

The matches list is now a list that's in time order.  This makes
working out what the next, and previous matches are considerably more
straightforward.
Merge remote-tracking branch 'pete/master'

Maintain the current_match() function at the moment, having it call
match_at() with now.
Remove duplicate current_match() def
Update submodule & change to canonical source.

Change-Id: Ibc0c7e11e765430babbfe3b36651960cd4c9b03f
Merge remote-tracking branch 'sr/master'