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
Merge branch 'master' of github.com:flpjck/flapjack into 159_surface_ack_duration
Merge pull request #222 from ali-graham/159_surface_ack_duration

Surface acknowledgement duration