Adding hiera default values

While Hiera is not set properly (on the first run, for example)
applying 'puppet::agent' class will fail with "Error: Could not
find data item puppet::agent::server in any Hiera data file and
no default supplied at
/tmp/vagrant-puppet/modules-0/puppet/manifests/agent.pp:36 on
node nodename".
With this change the 'puppet::agent' will be successfully applied,
albeit using the default value.
I think 'puppet' is a good default server name to use.
Merge pull request #21 from ttres/hiera-defaults

Adding hiera default values
Turning repos optional

In some circumstances the Puppet Labs packages repositories
configuration should not be enforced (behind corporate proxy,
or when it is already configured, for example).
The default case should be to configure (true), but with the
class parameter $add_puppet_repos now there's an option to not
to do.
Update the parameter name to 'manage_repos'
Merge branch 'turn-repos-optional'