Apple contribution for OSX SSE and iOS NEON optimizations unit tests, thanks to Jordan Hubbard, Ian Ollmann and Hristo Hristov.

For OSX:
cd build
./premake_osx xcode4
for iOS:
cd build
./ios_build.sh
./ios_run.sh

Also integrated the branches/StackAllocation to make it easier to multi-thread collision detection in the near future. It avoids changing the btCollisionObject while performing collision detection.

As this is a large patch, some stuff might be temporarily broken, I'll keep an eye out on issues.

src/BulletDynamics/ConstraintSolver/btGeneric6DofConstraint.h

@@ -268,7 +268,7 @@ This brings support for limit parameters and motors. </li>
 </ul>
 
 */
-class btGeneric6DofConstraint : public btTypedConstraint
+ATTRIBUTE_ALIGNED16(class) btGeneric6DofConstraint : public btTypedConstraint
 {
 protected:
 
@@ -346,6 +346,8 @@ protected:
 
 public:
 
+	BT_DECLARE_ALIGNED_ALLOCATOR();
+	
 	///for backwards compatibility during the transition to 'getInfo/getInfo2'
 	bool		m_useSolveConstraintObsolete;