3D touch events support

[matt-gadd]

Also received a request today asking what our plan is for supporting 3D touch events. https://github.com/freinbichler/3d-touch and https://pressurejs.com/ are a few implementations, so it seems possible.
@dylans

iOS supports force touch, we should decide whether we want to support this as a first class citizen in widget-core (and if so what the equivalent fallback would be on non force touch devices). Or whether we just support being able to hook into supporting this.

[kitsonk]

I would recommend we close this, until there is a compelling use case. At the moment, there is nothing prohibiting anyone and with the widget-core/meta, creating a 3d touch manager should be fairly straight forward, but there is a lot of other stuff to focus on and would not be a priority anytime soon.

[dylans]

I've moved it to long-grass (which is sort of intended for post 2.0 things that we may consider doing). At some point we can look at the long-grass items and probably close them all out if you prefer.