Merge pull request #12 from larstobi/feature/check_names

Add support for $check_names
Remove quotes for check-names.
Merge pull request #13 from larstobi/feature/fix_quoted_check_names

Remove quotes for check-names.
RedHat and Debian systems have different path for 'directory' variable.
Fix RSpec test. Service is now found using default PATH.
Split out options from named.conf.erb
Added root_servers_file parameter and template logic.
Concat named.conf.erb and named.conf.options.erb templates.