Leverage touch-action whenever possible

[RByers]

If the browser supports touch-action then disable the tap delay explicitly by disabling the double-tap-to-zoom gesture and not installing touch listeners at all.

Setting touch-action to manipulation on an element (when not already set to something else) has no other impact than disabling double-tap (which normal FastClick code does anyway), so there shouldn't be much (any?) downside to this approach. It has several advantages to the existing behavior:

• doesn't require the author to know they need to explicitly opt-in to touch-action
• avoids the potential scroll performance impact of installing non-passive touch listeners
• doesn't disable browser-defined tap recognition features such as touch adjustment (small target handling), tap suppression (don't click on a tap during a fling), system-defined slop regions (eg. different Android devices can have different configurations for how much movement is permitted for a 'tap').

Fixes #498

[RByers]

Note that I haven't tested this yet - just wanted to propose a simple possible fix.

[calebfaruki]

This fix worked to resolve a bug I was experiencing with iOS Safari 9.1 and above, since the 350ms delay was removed.

https://developer.apple.com/library/content/releasenotes/General/WhatsNewInSafari/Articles/Safari_9_1.html#//apple_ref/doc/uid/TP40014305-CH10-SW8