Fix so that parentheses can be written from iOS devices.

    * changed the type of the input field (which is used for bringing up the
      on-screen keyboards on touch devices) from email to text
    * when typing in an input field of type email the user is not allowed to
      write parentheses on iOS devices, the keys are disabled.
    * tested on iOS 6, iOS 7 and Android 4.3.

vnc.html

@@ -66,7 +66,7 @@
                 <input type="image" src="images/keyboard.png"
                     id="showKeyboard" class="noVNC_status_button"
                     value="Keyboard" title="Show Keyboard"/>
-                <input type="email" autocapitalize="off" autocorrect="off"
+                <input type="text" autocapitalize="off" autocorrect="off"
                     id="keyboardinput" class="" value="&nbsp;"/>
             </div>
         </div>