Added Explorer class.
World now exposes its Graph.
Removed unused usings in World.cs.
Added SeekAtSteering.
Implemented SeekAtSteering.Steer method.
Added default constructor to SeekAtSteering.
SeekSteering now uses SeekAtSteering internally.
Merge branch 'master' into explorer
Explorer now has steeringbehavior, an enumerator and a graph.
Explorer now has an Initialize method.
Explorer now has Update implemented.
Explorer now has Paint implemented.
TestWorldfactory now creates an Explorer.
Explorer now sets _current in Initialize.
Explorer now sets the location of SeekAt.