Notify of changed results only if the results actually changed

[nathanielhourt]

Currently the server is more or less spamming the client with 'new' results (which are actually the same as the old ones) on a contest because it's too dumb to detect whether the new results are the same as the old ones or not. Fix this so that the server only notifies the client(s) of new results if the results are actually new.

[nathanielhourt]

Note that this is responsible for the replaced decision lists closing immediately after being expanded (bottom of the contest detail page)