Adding broadcast(client), manycast and multicast template stanzas and params

This adds the possibility to create an ntp.conf file which contains stanzas to use e.g. broadcast instead of server. It's been tested on: Gentoo, CentOS, Debian. Spec tests are unaffected. 

Only a few files are changed: params.pp and init.pp to allow for the new parameters. Plus all the templates to put the new stanzas in.