Restart the correct service when installing libvirt support
include the tftp proxy class before evaluating the settings template
workaround parse-time dependency to accessing ::tftp::data_dir; also actually use that variable
A few fixes to enable installing a proxy without the foreman server
Add ISC dhcpd management

For full functionality, the dhcpd needs to have the proxy_dhcp_omapi_key
configured with the name "proxy_key" according to the HOWTO at

   http://projects.theforeman.org/projects/smart-proxy/wiki/ISC_DHCP
Merge pull request #15 from DavidS/master

More work: configuring TFTP and DHCP