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/NativeClient/tumbler_module.cc

@@ -0,0 +1,45 @@
+// Copyright (c) 2011 The Native Client Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tumbler.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/gles2/gl2ext_ppapi.h"
+
+/// The Module class.  The browser calls the CreateInstance() method to create
+/// an instance of your NaCl module on the web page.  The browser creates a new
+/// instance for each <embed> tag with type="application/x-nacl".
+class TumberModule : public pp::Module {
+ public:
+  TumberModule() : pp::Module() {}
+  virtual ~TumberModule() {
+    glTerminatePPAPI();
+  }
+
+  /// Called by the browser when the module is first loaded and ready to run.
+  /// This is called once per module, not once per instance of the module on
+  /// the page.
+  virtual bool Init() {
+    return glInitializePPAPI(get_browser_interface()) == GL_TRUE;
+  }
+
+  /// Create and return a Tumbler instance object.
+  /// @param[in] instance The browser-side instance.
+  /// @return the plugin-side instance.
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new tumbler::Tumbler(instance);
+  }
+};
+
+namespace pp {
+/// Factory function called by the browser when the module is first loaded.
+/// The browser keeps a singleton of this module.  It calls the
+/// CreateInstance() method on the object you return to make instances.  There
+/// is one instance per <embed> tag on the page.  This is the main binding
+/// point for your NaCl module with the browser.
+Module* CreateModule() {
+  return new TumberModule();
+}
+}  // namespace pp
+