Core/MMAPS: Fix invisible wall issue in MMAPS.

Fix invisible wall issues in MMAPS caused by tile connections not being extracted correctly.
This reverts aa645683b8 and restores an old version of recastnavigation, most likely https://github.com/memononen/recastnavigation/commit/1be9de72d87dcfdecf6bea30f5461745f7d7afe6 .

Re-extracting MMAPS is required.

src/server/game/Movement/PathGenerator.cpp

@@ -581,7 +581,7 @@ bool PathGenerator::HaveTile(const G3D::Vector3& p) const
     if (tx < 0 || ty < 0)
         return false;
 
-    return (_navMesh->getTileAt(tx, ty, 0) != NULL);
+    return (_navMesh->getTileAt(tx, ty) != NULL);
 }
 
 uint32 PathGenerator::FixupCorridor(dtPolyRef* path, uint32 npath, uint32 maxPath, dtPolyRef const* visited, uint32 nvisited)