add kd tree class

add mesh decimation algorithm

src/Mod/Mesh/App/Mesh.cpp

@@ -51,6 +51,7 @@
 #include "Core/Triangulation.h"
 #include "Core/Trim.h"
 #include "Core/Visitor.h"
+#include "Core/Decimation.h"
 
 #include "Mesh.h"
 #include "MeshPy.h"
@@ -940,6 +941,12 @@ void MeshObject::smooth(int iterations, float d_max)
     _kernel.Smooth(iterations, d_max);
 }
 
+void MeshObject::decimate(float fTolerance, float fReduction)
+{
+    MeshCore::MeshSimplify dm(this->_kernel);
+    dm.simplify(fTolerance, fReduction);
+}
+
 Base::Vector3d MeshObject::getPointNormal(unsigned long index) const
 {
     std::vector<Base::Vector3f> temp = _kernel.CalcVertexNormals();