Support for devices with both a mouse and touch events

[jfyne]

At the moment backbone.touch doesn't play nicely with devices that have both a touch event and a mouse available. I believe this change will help to alleviate this problem, however I don't have many devices to test on. Can you take a look and see if you think this will help?

My issue has occurred within my application with users who have a Chromebook Pixel not being able to click on any links with the mouse pad. I don't have a Chromebook Pixel to test on either, but I will be pushing out this change to my users to see if it fixes it.

Cheers!

[mvantassel]

This PR fixed an issue we had in production for a client. Thank you very much @jfyne for this!

[nervetattoo]

Thanks for the PR @jfyne, I've been too busy to have a look at this and getting it merged.
I would love it if it was possible to write a test case for this, but I will probably merge it without as well.

[nervetattoo]

Using the low level event binding methods isn't ideal imo, and I'd also prefer that this was solved by detection before attaching events, not this removing after event happened and then delegating events all over.
Event binding has a cost and this is too much binding/removing, at least when this is repeated over every view instance in an entire app which can be thousands.