Merge pull request #117 from elly/integration-changelog

Update CHANGELOG for integration tests.
Refactor event loop.

Refactor the event loop to be modular and testable. Also, add support for
detecting corruption of the realtime clock, as can be caused by suspend/resume
cycles without an rtc battery. The event loop is now driven by a tree of events,
which are either sources (currently suspend/resume events, periodic events, and
network route events) or composite events.

Signed-off-by: Elly Fong-Jones <elly@leptoquark.net>