[manifest] Add support for disabling pull-to-refresh (#398)

Android has a default overscroll action of refreshing the page. Many appy sites either provide their own pull-to-refresh implementation, or want to explicitly disable it. While developers can use programmatic and declarative means to disable the effect, it's not always convenient (see http://stackoverflow.com/questions/29008194/disabling-androids-chrome-pull-down-to-refresh-feature). Having a manifest key for disabling the feature (or perhaps other content targeting gestures like gesture nav on desktop) would be nice.

@slightlyoff what do you think? 

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/manifest/issues/398