getPrecision use Math.round instead of | 0 to avoid precision problem

Author: pissang

src/util/number.js

@@ -74,7 +74,7 @@ define(function() {
     function getPrecision(val) {
         var e = 1;
         var count = 0;
-        while (((val * e) | 0) / e !== val) {
+        while (Math.round(val * e) / e !== val) {
             e *= 10;
             count++;
         }