Move "set hostname" action to external yml file in common/tasks/hostname.yml
Add stubs for Hadoop installation and configuration
Update names of plays
Fix typos

	modified:   hadoop/tasks/packages.yml
Update hadoops plays
Ansible does not like `file:` in the `name` tag!
fix typo and syntax error
Working playbooks for Hadoop. Very basic.
	modified:   roles/hadoop.yml
	new file:   roles/hadoop/tasks/conf.yml
	modified:   roles/hadoop/tasks/packages.yml
	new file:   roles/hadoop/templates/core-site.xml.j2
	new file:   roles/hadoop/templates/hdfs-site.xml.j2
	new file:   roles/hadoop/templates/mapred-site.xml.j2
	new file:   roles/hadoop/templates/masters.j2
	new file:   roles/hadoop/templates/slaves.j2
Remove unused files

	deleted:    roles/hadoop/tasks/datanode.yml
	deleted:    roles/hadoop/tasks/jobtracker.yml
	deleted:    roles/hadoop/tasks/namenode.yml
	deleted:    roles/hadoop/tasks/tasktracker.yml