Add speed factor for radio button ripple

Author: tinayuangao

src/lib/radio/radio.html

@@ -9,6 +9,7 @@
     <div md-ripple *ngIf="isRippleEnabled()" class="md-radio-ripple"
          [md-ripple-trigger]="getHostElement()"
          [md-ripple-centered]="true"
+         [md-ripple-speed-factor]="0.3"
          md-ripple-background-color="rgba(0, 0, 0, 0)"></div>
   </div>