Add the old Bullet 2.x obsolete demos, and CMake buildsystem files, and gradually move them to newer Bullet 3.x structure

Use statically linked freeglut, instead of dynamic glut for the obsolete Bullet 2.x demos
Add the 'reset' method to b3GpuDynamicsWorld, and use it in the BasicGpuDemo (pretty slow in debug mode, use release mode)
Don't crash in btCollisionWorld, if there is no collision dispatcher

ObsoleteDemos/OpenGL/GlutDemoApplication.cpp

@@ -0,0 +1,87 @@
+
+#ifndef _WINDOWS
+
+#include "GlutDemoApplication.h"
+
+#include "GlutStuff.h"
+
+#include "BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h"
+#include "BulletDynamics/Dynamics/btRigidBody.h"
+
+void	GlutDemoApplication::updateModifierKeys()
+{
+	m_modifierKeys = 0;
+	if (glutGetModifiers() & GLUT_ACTIVE_ALT)
+		m_modifierKeys |= BT_ACTIVE_ALT;
+
+	if (glutGetModifiers() & GLUT_ACTIVE_CTRL)
+		m_modifierKeys |= BT_ACTIVE_CTRL;
+	
+	if (glutGetModifiers() & GLUT_ACTIVE_SHIFT)
+		m_modifierKeys |= BT_ACTIVE_SHIFT;
+}
+
+void GlutDemoApplication::specialKeyboard(int key, int x, int y)	
+{
+	(void)x;
+	(void)y;
+
+	switch (key) 
+	{
+	case GLUT_KEY_F1:
+		{
+
+			break;
+		}
+
+	case GLUT_KEY_F2:
+		{
+
+			break;
+		}
+
+
+	case GLUT_KEY_END:
+		{
+			int numObj = getDynamicsWorld()->getNumCollisionObjects();
+			if (numObj)
+			{
+				btCollisionObject* obj = getDynamicsWorld()->getCollisionObjectArray()[numObj-1];
+
+				getDynamicsWorld()->removeCollisionObject(obj);
+				btRigidBody* body = btRigidBody::upcast(obj);
+				if (body && body->getMotionState())
+				{
+					delete body->getMotionState();					
+				}
+				delete obj;
+
+
+			}
+			break;
+		}
+	case GLUT_KEY_LEFT : stepLeft(); break;
+	case GLUT_KEY_RIGHT : stepRight(); break;
+	case GLUT_KEY_UP : stepFront(); break;
+	case GLUT_KEY_DOWN : stepBack(); break;
+	case GLUT_KEY_PAGE_UP : zoomIn(); break;
+	case GLUT_KEY_PAGE_DOWN : zoomOut(); break;
+	case GLUT_KEY_HOME : toggleIdle(); break;
+	default:
+		//        std::cout << "unused (special) key : " << key << std::endl;
+		break;
+	}
+
+	glutPostRedisplay();
+
+}
+
+void GlutDemoApplication::swapBuffers()
+{
+	glutSwapBuffers();
+
+}
+
+#endif //_WINDOWS
+
+