Install PhantomJS

This is required for UserGuidelines/Admin/MapPrinting.

This is not avaialble in Debian Wheezy, but is in Debian SID (unstable) so we can use ​apt-pinning:

cat << EOF >> "/etc/apt/sources.list"
deb     http://http.debian.net/debian jessie      main
deb     http://http.debian.net/debian sid         main
EOF
cat << EOF > "/etc/apt/preferences.d/preferences"
Package: *
Pin: release a=stable
Pin-Priority: 700

Package: *
Pin: release a=testing
Pin-Priority: 650

Package: *
Pin: release a=unstable
Pin-Priority: 600
EOF
apt-get update
apt-get -yt testing install phantomjs