Use cached math library functions in UUID.

Foundation/CPString.j

@@ -673,7 +673,7 @@ var CPStringHashes      = new objj_dictionary();
     var g = @"";
     
     for(var i = 0; i < 32; i++)
-        g += Math.floor(Math.random() * 0xF).toString(0xF);
+        g += FLOOR(RAND() * 0xF).toString(0xF);
     
     return g;
 }