use size_t instead of int, for allocator

added hashtable based PairManager, thanks Pierre Terdiman and Erin Catto
improved friction in 'cachefriendly' solver
moved 'refreshcontactpoints' into collision detection, instead of solver
avoid linear search for contact manifolds, by storing an index
ignore margin for sphere shape (its entire radius is already margin)
avoid alignment checks in BVH serialization, they don't compile on 64-bit architectures
made 'bomb' box more heavy

src/BulletCollision/BroadphaseCollision/btBroadphaseProxy.h

@@ -65,6 +65,7 @@ CONCAVE_SHAPES_END_HERE,
 
 ///btBroadphaseProxy
 ATTRIBUTE_ALIGNED16(struct) btBroadphaseProxy
+//struct btBroadphaseProxy
 {
 
 BT_DECLARE_ALIGNED_ALLOCATOR();
@@ -96,6 +97,12 @@ BT_DECLARE_ALIGNED_ALLOCATOR();
 
 	};
 
+	int			m_uniqueId;//m_uniqueId is introduced for paircache. could get rid of this, by calculating the address offset etc.
+	inline int getUid()
+	{
+		return m_uniqueId;//(int)this;
+	}
+
 	//used for memory pools
 	btBroadphaseProxy() :m_clientObject(0){}
 
@@ -106,6 +113,8 @@ BT_DECLARE_ALIGNED_ALLOCATOR();
 	{
 	}
 
+	
+
 	static inline bool isPolyhedral(int proxyType)
 	{
 		return (proxyType  < IMPLICIT_CONVEX_SHAPES_START_HERE);