Merge pull request #14 from axelrodR/master

Bugfix: A typo in dividePoly can cause stack overrun when several vertices happen to fall exactly on cell boundaries
Fix for U-turn path case
Merge pull request #15 from axelrodR/master

bugfix: divPoly caused a stack overrun by producing an 8th point
improving path aesthetics at tile crossing: in the old code, when a new node is found a single 3D position is associated with it. This position is used regardless of arriving from a new tile. A minor issue on a normal navmesh, this produces many problems when crossing tiles. Points might be located on different borders altogether depending on where one arrived from first.
The new code assigns several (consecutive) dtNodes for polygons that lie on tile boundary. Each node gets its own point. since the nodes are packed together consecutively, it is easy to find the right node by reference even though there are several.
fix: multiple node allocation had a bug
moving from creating several nodes at once for the same ref to creating as needed based on ref and state (where state is currently used only for border poly to keep the arrival side).