defaultValue of 0 now displayed

previously treated as empty string when passed to input text/textarea

src/dom/components/ReactDOMInput.js

@@ -48,7 +48,7 @@ var ReactDOMInput = ReactCompositeComponent.createClass({
   getInitialState: function() {
     return {
       checked: this.props.defaultChecked || false,
-      value: this.props.defaultValue || ''
+      value: this.props.defaultValue != null ? this.props.defaultValue : ''
     };
   },
 

src/dom/components/ReactDOMTextarea.js

@@ -77,7 +77,9 @@ var ReactDOMTextarea = ReactCompositeComponent.createClass({
       );
       defaultValue = '' + children;
     }
-    defaultValue = defaultValue || '';
+    if (defaultValue == null) {
+      defaultValue = '';
+    }
     return {
       // We save the initial value so that `ReactNativeComponent` doesn't update
       // `textContent` (unnecessary since we update value).