Implements Flying/Drinking/Attending FSMs

Adds Messages to handle stateful FlightAttendant
Adds tests to check stateful flight attendants.

Some of the FlightAttendantSpec tests happen far too quickly on a local
instance for the state changes to be perceived by the test system
without implementing sleeps or large delays in the scheduler. The tests
are left to express a design intent instead of as functional tests.

Creates HeadingIndicator equipment actor
Adds HeadingIndicator to plane
Completes Flyingbehavior
Adds DrinkingBehavior
Implements FlyingBehavior FSM and Drinking Pilot
Merge pull request #14 from jackcviers/state

Implements Flying/Drinking/Attending FSMs