Rework Route finding Code

[BenSmithers]

Right now the path-finding code is hard-coded into the Hex definition. It also explicitly depends on the overland module code. This is bad! Path finding should depend on the module

Idea: modules implement heuristic/cost functions based on two arbitrary hexes. These functions should be handed down to the Clicker by the main launch script.

• Route Finding (A* implementation) should be module-dependent

[BenSmithers]

Moved the route finding entirely into the clicker_tool.py file, so rivers, roads, mobiles, etc. can all effect the route costs. Also added route options as an enum so different cost calculation methods can be used depending on what kind of route is asked for.