Allow loading as an ES6/CommonJS module

[digitalsadhu]

It looks like L needs to be present on the window object for this plugin to work. Leaflet is now available on npm so you can:
var L = require('leaflet')
Since this exposes no global L object, I'm assuming it won't be possible to use this module without shimming.
Is this correct or am I missing something?

[leplatrem]

Hi !

To be honest we haven't worked on this at all.

@perliedman did it on Leaflet.GeometryUtil using this piece of code : https://github.com/makinacorpus/Leaflet.GeometryUtil/blob/master/dist/leaflet.geometryutil.js#L1-L17

If you want to contribute this here too, it will be merged with pleasure ! :)

Thanks !

[perliedman]

Yeah, that's the "UMD wrapper". I think there might be a slightly better version of it these days.

This might be the authoritative source: https://github.com/umdjs/umd/blob/master/returnExports.js