Instructions in UbuntuInstallationWiki page obsolete

[chakradarraju]

Instructions given here: https://github.com/mapnik/mapnik/wiki/UbuntuInstallation#ubuntu--1110-and--1404

fail with following error when I run apt-get update:
E: The repository 'http://ppa.launchpad.net/mapnik/v2.2.0/ubuntu artful Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

Also please include instructions for installing mapnik using apt-get for ubuntu after 1404