fix failing test
jabber command to query for check maintenance status

also some refactoring for the EntityCheck model; moves the
event creation to the Event model, collapses some methods
with common functionality.
cherry-pick fix for change in thin internals
show maintenance times in web check page, allow re-ack through filter
Merge branch 'master' of github.com:flpjck/flapjack into 159_surface_ack_duration
jabber output fixes
refactoring on Event, some tests
refactoring for consistent variable naming
improve tests for Event data model
cherry-pick fix for change in thin internals
list last 20 states in web check detail page
notification summaries on check details page
always update check status on event
create scheduled maintenance for new checks
allow nil/missing media intervals for contacts via API
Merge branch 'master' of github.com:flpjck/flapjack into 153_allow_media_interval_removal
Merge branch 'master' of github.com:flpjck/flapjack into 218_sched_maint_for_new_checks
Merge branch 'master' of github.com:flpjck/flapjack into 221_always_update_check_summary
Merge branch 'master' of github.com:flpjck/flapjack into 216_web_summarise_state_changes
Merge branch 'master' of github.com:flpjck/flapjack into 159_surface_ack_duration