Usability on small screens review

[KatieWoe]

Per @kathy-phet's request in phetsims/qa#295 I am making issues in each published sim repo detailing the pointer areas and usability of sims on phone sized screens. Done on an iPhone 7 iOS 12 device.

Potential Difficulties Noticed:

• Arrows at end of sliders could have larger pointer areas

Screenshots:

[arouinfar]

@Denz1994 asymmetric dilation of NumberControl tweakers was added in phetsims/scenery-phet#489. Here's a mockup of updated touch areas in green.

[Denz1994]

I've updated the arrow's at the end of the NumberControls to have dilated touch areas. @arouinfar Please check master for MAS and MASB for the changes.

[arouinfar]

Thanks @Denz1994. The Gravity tweakers are looking good, but I think the Mass tweakers are still feeling a bit small. Can you add some extra vertical padding to the Mass tweakers?

I know it looks a bit exaggerated, but the Mass NumberControl is somewhat on the smaller side, so the exaggerated touch area would be helpful.

[Denz1994]

This makes sense. The touch areas have been expanded along the Y-axis. Please review master @arouinfar?

[arouinfar]

Looks great, thanks @Denz1994!