pathfinder: Change to C++ file
pathfinder: Use STL implementation of list and heap
pathfinder: Use C++ style casts
Merge branch 'pathfinder-c++'

Convert pathfinder to C++.
Merge commit 'b832c69588c6fce18665f384f9445f0607973b96' into Abstracting-graphics-and-data-source

Conflicts:
	Makefile.am