Test events are sent to automate model

This is the initial PR of a test that validates CFME events are passed through automate. (see [BZ-958277](https://bugzilla.redhat.com/show_bug.cgi?id=958277)) It will be extended later to test different classes of events.

It uses an API listener (Bottle) as a bridge between automate and py.test. The listener runs in the background. The listener may be run standalone for manual testing (`tests/common/listener.py`)

Before testing update cfme_data with the IP of the py.test machine and also verify there's at least one VM listed under "test_vm_power_control".

Requires [cfme_pages PR #130](https://github.com/RedHatQE/cfme_pages/pull/130)