Fixed warnings in Bullet/src core library

Thanks Martijn Reuvers from Two Tribes B.V. (www.twotribes.com) for the patch

To make this work more visible, suppress warnings in external libraries in Extras (COLLADA_DOM, libxml and glui contain many warnings)
Added PreprocessorDefinitions: _CRT_SECURE_NO_DEPRECATE;_CRT_NONSTDC_NO_DEPRECATE to vcproj files

src/BulletCollision/CollisionShapes/btCollisionShape.cpp

@@ -21,7 +21,12 @@ subject to the following restrictions:
   can be used by probes that are checking whether the
   library is actually installed.
 */
-extern "C" void btBulletCollisionProbe () {}
+extern "C" 
+{
+void btBulletCollisionProbe ();
+
+void btBulletCollisionProbe () {}
+}