PathFinder: Dijkstra Method

Contribution to Julien Lecomte's post. AI path finder now goes diagonally too, less memory intensive. All credit goes to original author; if you wish to comment on the diagonal path routine, please do; otherwise any voting should go to the original author at www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=31654&lngWId=1