fixed possible field conflict.

std/Std.hx

@@ -195,7 +195,7 @@ class Std {
 		#if flash
 		__random__(x);
 		#else neko
-		Math._rand_int(Math._rnd,x);
+		Math._rand_int(Math.__rnd,x);
 		#else js
 		Math.floor(Math.random()*x);
 		#else error

std/neko/NekoMath__.hx

@@ -45,7 +45,7 @@ class NekoMath__
 	static var acos = Lib.load("std","math_acos",1);
 	static var pow = Lib.load("std","math_pow",2);
 
-	static var _rnd = Lib.load("std","random_new",0)();
+	static var __rnd = Lib.load("std","random_new",0)();
 	static var _rand_float = Lib.load("std","random_float",1);
 	static var _rand_int = Lib.load("std","random_int",2);
 	static function random() { return _rand_float(_rnd); }