[Button] Expose disableTouchRipple (#6234)

* Update FlatButton to expose disableTouchRipple

- The enhanced button wrapper exposes an option to disable
  touch ripples.  This is the case with the IconButton and
  should be persisted to the FlatButton.
- In addition to exposing the prop, the documentation page
  will be automatically updated with the new prop for Icon Button
  as well, since the documentation for the props is pulled strictly
  from the FlatButton component

* Update RaisedButton to expose disableTouchRipple

- The enhanced button wrapper exposes the option to
  disable touch ripples.  This is the case with the
  FlatButton component and should be exposed on
  RaisedButton for consistency.
- In addition to exposing the prop,
  the documentation page will automatically be
  updated with the newly defined prop from the
  RaisedButton component

src/FlatButton/FlatButton.js

@@ -46,6 +46,10 @@ class FlatButton extends Component {
       PropTypes.string,
       PropTypes.element,
     ]),
+    /**
+     * If true, the element's ripple effect will be disabled.
+     */
+    disableTouchRipple: React.PropTypes.bool,
     /**
      * Disables the button if set to true.
      */

src/RaisedButton/RaisedButton.js

@@ -144,6 +144,10 @@ class RaisedButton extends Component {
       PropTypes.string,
       PropTypes.element,
     ]),
+    /**
+     * If true, the element's ripple effect will be disabled.
+     */
+    disableTouchRipple: React.PropTypes.bool,
     /**
      * If true, the button will be disabled.
      */