Expose title prop of Button and Badge (#617)

Author: tcbegley

src/components/Badge.js

@@ -150,7 +150,12 @@ Badge.propTypes = {
   /**
    * Target attribute to pass on to the link. Only applies to external links.
    */
-  target: PropTypes.string
+  target: PropTypes.string,
+
+  /**
+   * Sets the title attribute of the underlying HTML button.
+   */
+  title: PropTypes.string
 };
 
 export default Badge;

src/components/Button.js

@@ -159,6 +159,11 @@ Button.propTypes = {
    */
   size: PropTypes.string,
 
+  /**
+   * Sets the title attribute of the underlying HTML button.
+   */
+  title: PropTypes.string,
+
   /**
    * Set outline button style, which removes background images and colors for a
    * lightweight style.