FIX: use btScalar instead of float, otherwise double precision build breaks

FIX: make Maya plugin compile for Maya 8.0
FIX: btDbvt SSE doesn't compile for double precision builds

src/BulletCollision/CollisionDispatch/btBoxBoxDetector.cpp

@@ -226,9 +226,9 @@ void cullPoints2 (int n, btScalar p[], int m, int i0, int iret[])
     a = btScalar(j)*(2*M__PI/m) + A[i0];
     if (a > M__PI) a -= 2*M__PI;
     btScalar maxdiff=1e9,diff;
-#if defined(DEBUG) || defined (_DEBUG)
-    *iret = i0;			// iret is not allowed to keep this value
-#endif
+
+    *iret = i0;			// iret is not allowed to keep this value, but it sometimes does, when diff=#QNAN0
+
     for (i=0; i<n; i++) {
       if (avail[i]) {
 	diff = btFabs (A[i]-a);