Don't include Promise polyfill in library

[dariocravero]

Hi @nolanlawson, I hope you're well :). I was wondering if you'd consider a PR removing lie and asking library authors to polyfill Promise instead if they still want to support older browsers and inlining is-promise to reduce the overhead caused by browserify when bundling it? Thanks, Darío

[nolanlawson]

Hey sorry, but I'm kind of loath to offer this kind of option for every library I use that exposes Promises... currently you can remove lie very trivially by doing e.g.:

browserify -r promise-worker -x lie

However this was discussed recently in a generic way (w3ctag/polyfills#6) and so I have hopes that at some point bundlers like webpack and browserify may offer a generic solution to this problem.

As for is-promise, yeah I would accept a PR inlining it because it's silly to have a single dependency in the worker file. :)

[dariocravero]

Thanks for the link, that's an amazing conversation there ;). Will get to this sometime next week and do that little PR too. I'll leave this open as a reminder for myself mainly if that's alright. Thanks :)