edit_clarification: send notification for sender-only responses
refactor: CheckMessageServlet to make way for announcement checking
CheckMessage: respond when there's a new announcement waiting
CheckMessage: make dismissMessage work for announcements
edit_clarification: make announcement if responding to all teams
edit_clarification: on Ok/Cancel, release the submission if it isn't yet answered

This will allow another judge to see it and take care of it.
clarifications: have url point to specific clarification being answered
refactor: make edit_clarification and edit_submission have a common base class
clarifications: flash-highlight the selected clarification
rules: update all teams' scores when contest phase changes
scoreboard: fix display of non-default-color balloons
scoreboard: auto-refresh (every minute)
rules: fix bug where scoreboard setting could not be changed
scoreboard_order: change label from "ordinal" to "login id"

since ordinal no longer exists as a property
scoreboard_order: simplify logic
edit_submission: recalc results when minutes change
submit tab: fix a missing html close tag
submit tab: fix link to submission
submit tab: disallow submissions if contest start time is not defined

...or if the contest start time is in the future
...or if there's a contest clock and its run out
rules page: use ISO8601 date format