expose local inertia diagonal in C-API, PyBullet, through the 'getDynamicsInfo'

render the inertia boxes in examples/pybullet/examples/quadruped.py and examples/pybullet/examples/reset_dynamic_info.py
fix an issue where the original margin (0.04) was used to compute the inertia, instead of latest margin

examples/SharedMemory/SharedMemoryPublic.h

@@ -210,6 +210,10 @@ enum JointType {
 	eGearType=6
 };
 
+enum b3RequestDynamicsInfoFlags
+{
+	eDYNAMICS_INFO_REPORT_INERTIA=1,
+};
 
 enum b3JointInfoFlags
 {
@@ -266,7 +270,7 @@ struct b3BodyInfo
 struct b3DynamicsInfo
 {
 	double m_mass;
-	double m_localInertialPosition[3];
+	double m_localInertialDiagonal[3];
 	double m_lateralFrictionCoeff;
 };