This adds a copy to clipboard button and input with the style parameter
pre-populated after exporting a style to an anonymous gist. Also
includes the URL as an input next to the button.
Checking the Mapbox style spec properties to see whether or not
exponential should be allowed as the property type, defaulting to
categorical which appears to work for either type. Also re-orders zoom
and data function buttons, aligning zoom right if data not supplied.
Builds off of the ZoomSpecField component with separate options for
handling data-driven properties. Reuses most of the zoom field
functionality with tweaks that I tried to keep as small as possible, and
the layout is based off of comments on the existing issue.
pjsier