HTTP2 in DoneJS

A blog post announcing the release of HTTP2 support in DoneJS. This will include:

* done-serve sets up an HTTP2 server if `--key` and `--cert` are provided (HTTP2 requires SSL).
* done-ssr using PUSH on assets when in an HTTP2 server (note, this is currently only turned on for the incremental renderer, we can make it optional for the traditional renderer).
* Integration with steal-push maybe? (not implemented yet).
* Note that this can benefit HTTP1 as well by adding Preload headers (supported in Chrome and Safari ([issue](https://github.com/stealjs/steal-push/issues/4)))
* A little about incremental rendering and what it is (or should this be a separate post by itself?)

Note that I would like this to be a post about the features, not a guide. Perhaps there should be mini-guides about each feature and link to them from the blog post.