Pull request #2946: fix: newValue为0时不生效的问题

Merge in VISUAL/fineui from ~KIRA/fineui:master to master

* commit '3066d10d10c559c0c36d040944e9bd09b201d06a':
  fix: newValue为0时不生效的问题

src/core/4.widget.js

@@ -225,7 +225,7 @@
                 if (BI.isFunction(o.css)) {
                     var css = this.__watch(o.css, function (context, newValue) {
                         for (var k in css) {
-                            if (!newValue[k]) {
+                            if (BI.isNull(newValue[k])) {
                                 newValue[k] = "";
                             }
                         }