Swallow all touches when ClosePolicy.TouchOutside is used

I think the `ClosePolicy.TouchOutside` behaves a bit unexpectedly. My expectation was that that when touching outside the tooltip to close it that that touch would be not be passed on to another view. Instead, the current implementation will close the tooltip and allow another view to handle the touch additionally.

Here's an example of the current behavior. When I touch the bottom button when closing the top tooltip, the bottom tip is shown.

![bad](https://cloud.githubusercontent.com/assets/277576/4539218/8c3b206c-4dfa-11e4-93be-ac6232eec711.gif)

Here's an example of the behavior with this pull request. When I touch the bottom button when closing the top tooltip, the tooltip is hidden and the button press doesn't happen.

![good](https://cloud.githubusercontent.com/assets/277576/4539219/90957f68-4dfa-11e4-92c4-ce7737c18444.gif)

I realize this changes the behavior of already released functionality. If you'd like, I can create an additional `ClosePolicy` called `TouchOutsideExclusive` or something like that.

I'm also planning another pull request where the background of the `TooltipView` is dimmed, which makes this functionality even more necessary. If the view is dimmed, you don't want to be able to accidentally touch one of the other views.