document browser compatibility

[bargar]

Appreciate all the hard work, thanks 👍

I've been doing some testing of an app using ember-light-table in different browsers and am seeing e.g. grids working in Edge, IE 11 and IE 10, but not working (table content is blank) in IE9.

Would it be possible to have browser compatibility added to the docs?

[offirgolan]

@bargar thank you for bringing this to my attention. Ill make sure to add this in the next release cycle.

[gwak]

I had the same issue, but adding polyfills in ember-cli-build.js fixed it for me:

"ember-cli-babel": {
  includePolyfill: true
}

See #343