kore 1.2 (new formula)

This commit add's a new formular to Homebrew for Kore. Kore is a fast
SPDY capable web server for web development in C.

Look at https://kore.io/ for further information.
No need for a block if the only thing in `head` is a URL:

```ruby
head 'https://github.com/jorisvink/kore.git'
```