Completed TryMove

Added an overload.  Added code to allow for the movement based on the
current hex and the direction of travel.
TryMove is done

But we need to move some code around in order to draw the robot
correctly in the world hexgrid.
Adding interface to allow objects to be drawn.

Right now I'm just using robots, but I may want to add other stuff in
the future and I need a common interface to allow them to be drawn on
the board.
Color and Brush Shape come for the robot now

But I need to figure out how to get it drawn.
Commented out the highlight stuff

Not sure what this is for.  It makes a blue circle, but I can't remember
why this is there.
Removing selected prop, adding List<IWorldObject>

A hexagon might contain more than one type of object.  Right now we just
need to know it has something and how to draw it.  I imagine this
IWorldObject interface will be extended.
Added back selected

This breaks several things.  I have too much move login in the
presentation layer.  This stuff needs to go.
I can find the north adjact hex

If I compare points on the side, but not the side itself.
HexSide .Equals() is not working.
Changed side comparison from == to contains

This works, but the == operator should work for these sides.  Not sure
why it keeps return null.  Need those UTs.