required polyfills for older browser support

[gschrader]

I found that adding Object.assign and Array.prototype.includes polyfills I was able to get an older browser to work that I need to be able to support. This might also address #1201 I haven't had a chance to test IE yet.

I'm wondering if this is something that should be added to the project or if I should just patch my installs. I can raise a PR, I'm just not sure the best place to add them. Any thoughts?

[xrmx]

A PR would be appreciated of course, regarding the place to add them i suppose just add them as npm dependencies like the others js libraries and require them where needed?

[gschrader]

I think polyfills have to be global but I'll give it a try.

[ascott]

@gschrader what browser are you trying to support?

[gschrader]

@ascott It's the javafx webview browser, which I believe is based on an old version of webkit.

[gschrader]

I can confirm #1323 works with the javafx webview, thanks again @ascott