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/TinyRenderer/tgaimage.h

@@ -24,8 +24,10 @@ struct TGAColor {
     unsigned char bgra[4];
     unsigned char bytespp;
 
-    TGAColor() : bgra(), bytespp(1) {
-        for (int i=0; i<4; i++) bgra[i] = 0;
+    TGAColor() :  bytespp(1) 
+	{
+        for (int i=0; i<4; i++) 
+			bgra[i] = 0;
     }
 
     TGAColor(unsigned char R, unsigned char G, unsigned char B, unsigned char A=255) : bgra(), bytespp(4) {