Enable on-screen zoom controls for all screen sizes.

[InsertUser]

I'm submitting bug report/feature reques

Brief Description

On phone sized displays a zoom control will appear but on tablets they do not. For single node or smallbuilding scale edits this means there is no way to zoom out without a mouse, which is obviously lacking on most tablets

What is the motivation / use case for this feature?

What is the current behaviour, (attach relevant screenshots) ?

Map display loads at high zoom without ameans to zoom out.

What is the expected behaviour ?

Pinch to zoom should work or an on-screen zoom control should appear to allowtoychacreen users to zoom out easily.

When does this occur ?

"Large" touchscreen devices.

How do we replicate the issue ?

Open a smallchangeset on an android tablet in either Chrome or Firefox.

Please tell us about your environment:

Android tablet in either Chrome or Firefox.