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/BulletCollision/CollisionShapes/btBox2dShape.h

@@ -23,7 +23,7 @@ subject to the following restrictions:
 #include "LinearMath/btMinMax.h"
 
 ///The btBox2dShape is a box primitive around the origin, its sides axis aligned with length specified by half extents, in local shape coordinates. When used as part of a btCollisionObject or btRigidBody it will be an oriented box in world space.
-class btBox2dShape: public btPolyhedralConvexShape
+ATTRIBUTE_ALIGNED16(class) btBox2dShape: public btPolyhedralConvexShape
 {
 
 	//btVector3	m_boxHalfExtents1; //use m_implicitShapeDimensions instead
@@ -34,6 +34,8 @@ class btBox2dShape: public btPolyhedralConvexShape
 
 public:
 
+	BT_DECLARE_ALIGNED_ALLOCATOR();
+
 	btVector3 getHalfExtentsWithMargin() const
 	{
 		btVector3 halfExtents = getHalfExtentsWithoutMargin();