Added per triangle stretching force and damping. This gives more realistics results. Also updated the tests.

Saying goodbye to mass-spring system!

examples/testbed/tests/cloth_self_collision.h

@@ -34,7 +34,7 @@ public:
 		b3ClothDef def;
 		def.mesh = &m_clothMesh;
 		def.density = 1.0f;
-		def.structural = 100000.0f;
+		def.streching = 100000.0f;
 		def.thickness = 0.2f;
 		def.friction = 0.3f;