Add W3C Touch support for mobile browsers

[JamesMGreene]

This library does not currently support the "touch" events necessary for it to work on mobile browsers.

Adding support for mobile browsers also introduces extra complexity as the whole text selection interface works much differently than that of a desktop browser: i.e. long tap to select a word, then drag the cursor ends to expand it to your desired selection range. It may not be possible to achieve the desired parity for mobile browsers as they probably don't fire additional events for that selection expansion activity (boo!).

Start with this touch detection technique leveraged from jQuery Mobile:

var touchSupported = $.support.touch || "ontouchend" in document;

[JamesMGreene]

With regard to the original touch events, supposedly call e.preventDefault(); in the handler for touchend will prevent the mouse events from firing:
http://stackoverflow.com/questions/8503453/click-event-called-twice-on-touchend-in-ipad

However, I don't believe this is a good solution either. Rather, I would prefer to keep track of it in a "registrar" for that target element's textSelect handler.

[JamesMGreene]

Various iOS selection techniques to test:

• http://teachmeios.com/tag/select/
• http://m.cnet.com/news/ios-quick-tip-paragraph-text-selection/20033608?ds=1

[JamesMGreene]

Some implementation techniques for consideration to keep things fast (a.k.a. "GhostClick"):
https://developers.google.com/mobile/articles/fast_buttons#code

For example, notice how they only add listeners for touchmove and touchend in the handler for touchstart rather than having those listeners active all the time.

[JamesMGreene]

See also Issue #10 for improved mobile support for selection via polling.

[JamesMGreene]

More examples from Firefox:
https://developer.mozilla.org/en-US/docs/DOM/Touch_events

[JamesMGreene]

jQuery Mobile also uses an experimental set of events for vmouse to try to abstract the mouse vs. touch confusion away: https://github.com/jquery/jquery-mobile/blob/master/js/jquery.mobile.vmouse.js

[JamesMGreene]

More:

• http://stackoverflow.com/questions/14406161/listening-to-mousedown-and-touchstart-on-devices-that-use-touch-and-a-mouse-e-g
• http://quirksmode.org/m/tests/touch.html

[JamesMGreene]

Promising (based on GhostClick):

• http://stackoverflow.com/a/7019461/471696
• but see comments for potentially necessary tweaks:
  • http://stackoverflow.com/questions/7018919/how-to-bind-touchstart-and-click-events-but-not-respond-to-both#comment9123749_7019461
    • http://stackoverflow.com/questions/7018919/how-to-bind-touchstart-and-click-events-but-not-respond-to-both#comment9471000_7019461