Port navmesh

[PFGimenez]

In order to use the D* Lite algorithm, we need to be able to generate automatically a navmesh.

There are six classes to port.

Three structures:

• NavmeshNode, a node of the navmesh
• NavmeshEdge, a edge of the navmesh
• NavmeshTriangle, a triangle of the navmesh

The navmesh builder : NavmeshComputer
The navmesh itself : TriangulatedMesh
The Navmesh class is used to read / generate a navmesh.

Java sources : https://github.com/PFGimenez/The-Kraken-Pathfinding/tree/kraken-cpp/core/src/main/java/pfg/kraken/dstarlite/navmesh

English is the mandatory langage, please translate any french words.
Remember to comply with ROS style guide

[PFGimenez]

I wrote the headers of NavmeshNode, NavmeshEdge and NavmeshTriangle.