First draft of the Asciidoctor.js 1.5.0 release announcement

I'm not really satisfied, maybe we can write more about what's in the release ?
I think I'm too specific on how to use Asciidoctor.js but it's hard to write less. You can't really explain how to use Asciidoctor.js, if you don't explain a little bit of Opal... but do we want to explain how to use Asciidoctor.js in the release announcement ?

I really like the Asciidoctor 1.5.0 release announcement, maybe we can stick with this format ?

 * Highlights
  * Asciidoctor.js is Asciidoctor
  * Node package
  * Bower package


What do you think? 

Let's also add an section about the core tooling based on Asciidoctor.js, something like "Asciidoctor.js powers tooling". The purpose of this section is to callout that Asciidoctor.js is central to the tooling effort and that it powers the AsciiDoc preview plugins for Chrome, Firefox, Atom and Brackets and is also used to generate DocBook output in AsciidocFX.

This section can be just a few short paragraphs.