Add inverse kinematics example with implementations by Sam Buss.

Uses Kuka IIWA model description and 4 methods:
Selectively Damped Least Squares,Damped Least Squares,
Jacobi Transpose, Jacobi Pseudo Inverse
Tweak some PD values in Inverse Dynamics example and Robot example.

examples/ThirdPartyLibs/BussIK/Tree.h

@@ -0,0 +1,92 @@
+/*
+*
+* Inverse Kinematics software, with several solvers including
+* Selectively Damped Least Squares Method
+* Damped Least Squares Method
+* Pure Pseudoinverse Method
+* Jacobian Transpose Method
+*
+*
+* Author: Samuel R. Buss, sbuss@ucsd.edu.
+* Web page: http://math.ucsd.edu/~sbuss/MathCG
+*
+*
+This software is provided 'as-is', without any express or implied warranty.
+In no event will the authors be held liable for any damages arising from the use of this software.
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it freely,
+subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.
+*
+*
+*/
+
+#include "LinearR3.h"
+#include "Node.h"
+
+#ifndef _CLASS_TREE
+#define _CLASS_TREE
+
+class Tree {
+
+public:
+	Tree();
+
+	int GetNumNode() const { return nNode; }
+	int GetNumEffector() const { return nEffector; }
+	int GetNumJoint() const { return nJoint; }
+	void InsertRoot(Node*);
+	void InsertLeftChild(Node* parent, Node* child);
+	void InsertRightSibling(Node* parent, Node* child);
+
+	// Accessors based on node numbers
+	Node* GetJoint(int);
+	Node* GetEffector(int);
+	const VectorR3& GetEffectorPosition(int);
+
+	// Accessors for tree traversal
+	Node* GetRoot() const { return root; }
+	Node* GetSuccessor ( const Node* ) const;
+	Node* GetParent( const Node* node ) const { return node->realparent; }
+
+	void Compute();
+	
+	void Print();
+	void Init();
+	void UnFreeze();
+
+private:
+	Node* root;
+	int nNode;			// nNode = nEffector + nJoint
+	int nEffector;
+	int nJoint;
+	void SetSeqNum(Node*);
+	Node* SearchJoint(Node*, int);
+	Node* SearchEffector(Node*, int);
+	void ComputeTree(Node*);
+	
+	void PrintTree(Node*);
+	void InitTree(Node*);
+	void UnFreezeTree(Node*);
+};
+
+inline Node* Tree::GetSuccessor ( const Node* node ) const
+{
+	if ( node->left ) {
+		return node->left;
+	}
+	while ( true ) {
+		if ( node->right ) {
+			return ( node->right );
+		}
+		node = node->realparent;
+		if ( !node ) {
+			return 0;		// Back to root, finished traversal
+		} 
+	}
+}
+
+#endif