Set default Icon category as standard and make button icon category utility

Author: donnieberg

components/SLDSButton/index.js

@@ -67,6 +67,7 @@ class Button extends React.Component {
         <button className={this.getClassName()} {...props} onClick={click}>
           <Icon
           name={this.props.iconName}
+          category='utility'
           size={this.props.iconSize}
           className={'slds-icon'} />
           <span className="slds-assistive-text">{this.props.label}</span>

components/SLDSIcons.js

@@ -51,7 +51,7 @@ export const Icon = React.createClass({
 
     getDefaultProps() {
         return {
-            category: 'utility',
+            category: 'standard',
         };
     },