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.
Ideally an upstream report and make a patch in this formula that you submit upstream. If you change `PREFIX=blah` to `PREFIX?=blah` in a Makefile you can override PREFIX with an environment variable.