Add support for touch-action attribute for Polymer PointerEvents

[steida]

http://www.polymer-project.org/platform/pointer-events.html needs nonstandard touch-action attribute to work.

Btw, I don't know why React just don't render anything what user needs? Custom attributes should work OFTB. For control freaks there can be option React.doesNotAllowUnknownAttributtes = true.

[steida]

Please allow touch-action attribute.

[sophiebits]

React needs a list of properties so that it knows whether to use the property accessor or setAttribute when changing the attribute (and also to convert between camel-casing and dash-cased, though that's not as critical). We'd like to make it easy to configure React with custom attributes; sorry this isn't easy right now.

[syranide]

It seems your other issue #140 addresses this concern already and I don't see React adding this specific attribute to the global whitelist.