New state stubs, and small grouping improvements

Added two new stub states, Roam and GoToWaypoint. These were
suggested as part of a push to make SmallDomWorld more realistic.

Roam: 4 components - Random absolute direction, Wall following,
Momentum, Weak monkey avoidance.

GTW: Pick a random position and head towards it.

Both of these require GPS or equivalent sensors, to be added.