Use H5BP server configs

Checks out a stable version of h5bp/server-configs-nginx and applies it
to the /etc/nginx folder

http://goo.gl/pBfB4W

Misc:
Adds "restart nginx" handler

Moved nginx variables to defaults yml

formatting issues

Enable better default site to drop unknown requests
Added php5-memcache to php5 setup

Also took the liberty of storing PHP sessions using memcache as well
enable and optimize opcache caching
Disable Opcache for dev environment
Add fastcgi_param SCRIPT_FILENAME

This could be missing depending on Nginx package versions in Ubuntu so
we're adding it to ensure it's always there.
Always install memcached
Fix plugin name and parentheses.
Tagged playbook roles
Improved Vagrant/VirtualBox performance by enabling NFS and increasing host cpu/memory allocation
Fix #65 - Replace dots in cron file names

Debian and Ubuntu will ignore cron files with dots in the filenames.

See http://manpages.ubuntu.com/manpages/trusty/en/man8/cron.8.html
Hardcode Vagrant VM memory to 1GB