Added first hack at ANA* algorithm.  Currently it doesn't resort the
openlist as it should when encountering a new goal.  Haven't even
tried compiling it yet, but I just want a reasonable starting point
sitting under version control.
Change to get ANA* building, or at least to try and complie it.
Small changes to ANA* to get it to build.  Still not actually correct,
but things are looking up.
Cost updated whenever a new incumbent is found

Potential updated for all nodes whenever a new solution is found

Initial cost still isn't set right

Still haven't dealt with potential being undefined for h = 0 (or g =
cost if we reverse the computation)
Changed ANA* to a minimization problem rather than a maximization problem.

Dealt with the divison by zero case.

Still don't initialize cost appropriately.
Set up initial cost bound appropriately