APIv2 event list request

See #922. Simply returns a list of event keys for a specified year, or
defaults to current year if not specified.
Don't delete event teams in helper. Probably the cause of #928
Default CacheableHandler to use edge cache for 61 seconds.
properly compare json attributes in match manipulator
Only push if at least one match is dirty
new_matches may be None
Only enqueue matchstats if matches have been updated
1992 as lower limit for event list API
Merge pull request #925 from brandondean/event-api

APIv2 event list request
Don't set headers if no response
use textarea instead of text input for webcast json
flush event webcast when editing event
Merge remote-tracking branch 'upstream/master'
Fix improper call to parent class constructor
More fixing of improper call to parent class constructor
Sort events by both start and end dates
Don't hardcode year on webcasts page