Add support for library.json

[ivankravets]

Hi,

Would be glad to see support for library.json, a unified and independent library manifest (any framework, any platform).

If some fields/data are missed in library.json, we can discuss and add them. Any proposals are welcome.

P.S: It should help with resolving of this issue #6646

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See original discussion adafruit/DHT-sensor-library#118

[cmaglie]

I can't see how library.properties and library.json can be merged together, we have a completely different build system. Can't they just live on their own as it is now?

[pfeerick]

This feature request was never about merging the two, but adding support for more than just the library.properties manifest spec, allowing library authors the choice of what manifest format to use. i.e. if library.properties exists, use that... if library.json exists, use that... may the best format win! 😆 I for one would like to see this happen, but I can understand it'll take a while before it happens, if it does...