Review of Run App

@Fteacher if someone wants to submit some changes to apps/locale/custom.html so that you choose the locale but then get a bunch of options which you can tweak to suit you then I'm very happy to merge it. It's not a big deal for someone to implement.

@HughB thanks - that sounds like a much better approach - please could you submit a PR? I don't know quite why I thought Bangle.project would work :(

I remember now that when I'd done the route app there was a scaling factor applied (which is just a hackier version of what's done in your code): https://github.com/espruino/BangleApps/b­lob/bf44683bfe2640f9cbfdebb2f9d140b72505­31a4/apps/route/custom.html#L78-L81

And unsurprisingly the scale factor for the UK ended up at 0.6ish, which is exactly 336/560