Wordpress 4.6

A fork from https://hub.docker.com/_/wordpress/ and customized web server

Optional ENV:

1. WORDPRESS_DB_HOST (defaults: linked service with label "mysql")
2. WORDPRESS_DB_USER (defaults: root)
3. WORDPRESS_DB_PASSWORD (defaults: MYSQL_ROOT_PASSWORD ENV in linked service.)
4. WORDPRESS_DB_NAME (defaults:wordpress)