Fixes for broadphase/paircache determinism.

Revert definition for ATTRIBUTE_ALIGNED16, and try to force sizeof(btSolverConstraint) by using unions with btScalar, for non-btScalar data types.
Use btAssert and not assert.
Don't access btAlignedObjectArray elements, for zero sets

src/BulletCollision/BroadphaseCollision/btDbvt.cpp

@@ -424,9 +424,14 @@ btDbvt::~btDbvt()
 //
 void			btDbvt::clear()
 {
-	if(m_root)	recursedeletenode(this,m_root);
+	if(m_root)	
+		recursedeletenode(this,m_root);
 	btAlignedFree(m_free);
 	m_free=0;
+	m_lkhd		=	-1;
+	m_stkStack.clear();
+	m_opath		=	0;
+	
 }
 
 //