updated demos -> ALT + mouse uses Maya-style controls, replaced BMF_Fonts by GLDebugFont

fix debug drawing of btMultiSphereShape
added box2d demo
added experimental gpu 2d demo

Demos/ColladaDemo/ColladaDemo.cpp

@@ -25,7 +25,7 @@ subject to the following restrictions:
 
 #include "ColladaConverter.h"
 
-#include "BMF_Api.h"
+#include "GLDebugFont.h"
 #include <stdio.h> //printf debugging
 
 float deltaTime = 1.f/60.f;
@@ -101,6 +101,12 @@ int main(int argc,char** argv)
 	return glutmain(argc, argv,640,480,"Bullet COLLADA Physics Viewer http://bulletphysics.org",colladaDemo);
 }
 
+void ColladaDemo::initPhysics()
+{
+	const char* filename = "jenga.dae";
+	initPhysics(filename);
+}
+
 void	ColladaDemo::initPhysics(const char* filename)
 {
 	m_cameraUp = btVector3(0,0,1);