With this commit, Pathfinding is implemented in MaNGOS!
Thank you very much to all who contributed, especially to Faramir118 and qsa.
Please report bugs and required offmesh changes, so that they can be adressed
For *nix users of the extractor, help about compiling content of contrib/ can be found in forums
Also fix wrong use INVALID_HEIGHT as height value.
It must be used only for _check_ height, and DON'T must use as real height value.
Must fix some wrong height check results.
Signed-off-by: VladimirMangos <vladimir@getmangos.com>