Mods

a lot of stuff ... 
- fixes 
  - concat::setup is deprecated
  - every field (but the name) in mx records is optional
- additions
  - ablility to use a very simple upstream name server
  - ability to configure dnsmasq completely using a config_hash option
  - copy & save of originally commented config file before replacing it
- some optimizations
  - use a generic service name in case you want to reference it
  - make service state configurable (maybe you don't want to start it)
  - $config_dir of dnsmasq now optional