Update readme

[blewisio]

Update readme:

• Change examples to ES6 (Node v4 was recently set to end-of-life)
• Add "About" and "Table of Contents" headings
• Remove bower installation guide (not modern / well supported anymore)

[mubaidr]

@blewisio Thank you so much for the contributions. But I am not sure about the removal of browser installation part, can you please explain why do you think it should be removed?

[blewisio]

Hey @mubaidr, thanks for the response. To be clear, it's the bower part, not the browser part. Bower used to be more popular, but it's not anymore. Many consider it irrelevant now-a-days. This is directly from the top of the bower website:

...psst! While Bower is maintained, we recommend using Yarn and Webpack or Parcel for front-end projects read how to migrate!

If you want to leave it in, that'd be okay with me, but I don't think it's useful anymore as almost everybody is using Yarn/Webpack/Parcel.

[mubaidr]

@blewisio I am sorry, I don't know why I read it as browser. :(

Thanks once again! 👍