add support for displaying esri metadata

[jgravois]

resolves #4280

• restricts fetching metadata when zoomed to 13 or tighter
• adds a new line to the metadata panel when Esri imagery is active to display the individual provider (NAIP, DigitalGlobe, Municipality etc.)

[jgravois]

we have info on imagery accuracy and resolution too. if thats interesting, just say the word.

[bhousel]

we have info on imagery accuracy and resolution too. if thats interesting, just say the word.

This looks great! I do think people would be interested in seeing accuracy and resolution too, so go ahead and add 👍

Maybe we should just rename getVintage to getMetadata.. The object that it passes to the callback could have all kinds of useful stuff in it.

[jgravois]

pushed another commit to incorporate @bhousel's suggestions.

i didn't know how to internationalize '(m)' so i just hardcoded it.

[pnorman]

You shouldn't add brackets around units.

[jgravois]

You shouldn't add brackets around units.

thats fine by me. transifex would probably like it if i spelled out 'meters' anyway.

[bhousel]

You shouldn't add brackets around units.

thats fine by me. transifex would probably like it if i spelled out 'meters' anyway.

Thanks @jgravois ! I'll clean up the strings, but this is mostly fine. I'll merge it tomorrow morning.

FWIW the measurement pane and scale bar both have hardcoded unit strings for things like "m", "ft" etc, and nobody has complained yet. 👌

[bhousel]

Just merged this, thanks again @jgravois!