* Correct env variable name in minitor_test
* Adding more test environments, skipping python 3.5
because lack of assert_called_once support
* Using default travis python environments
Based on the idea from SeaLife, adds alerts for when a monitor comes out
of an alerting down state. Also includes a bunch of unit tests to cover
the new code.
An issue with the failure function caused the first alert after reaching
the minimum `alert_after` threshold to not notify unless using
exponential backoff.
New tests were added to reproduce the error and then it was fixed.
Fixes#2