Add tmp directory to ignoring list.
Modify Rakefile.
Add recipe for installing munin-node.

  - Package installation:
  - Downloading the munin-node debs.
  - Install munin-node debs.
  - Enable and start the munin-node service when booting.
  - Change the iptables rules in order to allow the munin-node communication.
Reload the network configuration.
Merge branch 'interfaces'
Add the default munin-node.conf.
Merge branch 'munin-node'