Replace XOR swapping by default ("naive", with extra var) one.

Ref: http://en.wikipedia.org/wiki/XOR_swap_algorithm, modern compilers/CPUs are much more efficient with "naive" algo than XOR one.
Doubled check, for me in an optimized build, XOR is several times slower than naive algo.

source/blender/blenlib/intern/edgehash.c

@@ -59,11 +59,9 @@ static const unsigned int _ehash_hashsizes[] = {
 #endif
 
 /* ensure v0 is smaller */
-#define EDGE_ORD(v0, v1) \
-	if (v0 > v1) {       \
-		v0 ^= v1;        \
-		v1 ^= v0;        \
-		v0 ^= v1;        \
+#define EDGE_ORD(v0, v1)            \
+	if (v0 > v1) {                  \
+		SWAP(unsigned int, v0, v1); \
 	} (void)0
 
 /***/

source/blender/bmesh/tools/bmesh_beautify.c

@@ -90,11 +90,9 @@ static GSet *erot_gset_new(void)
 }
 
 /* ensure v0 is smaller */
-#define EDGE_ORD(v0, v1) \
-	if (v0 > v1) {       \
-		v0 ^= v1;        \
-		v1 ^= v0;        \
-		v0 ^= v1;        \
+#define EDGE_ORD(v0, v1)   \
+	if (v0 > v1) {         \
+		SWAP(int, v0, v1); \
 	} (void)0
 
 static void erot_state_ex(const BMEdge *e, int v_index[2], int f_index[2])