Fix feature heading style in home page

Old heading style was misleading, as it look like a link.  This patch
update the heading style to h3 to solve this.

Fixes #2.

Signed-off-by: Tzach Livyatan <tzach@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Fix hard-coded URL in site configuration

Fixes "jekyll server" locally.

Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>