Improved #run_server to check if EM reactor is already running.
Also moved Thread creation to inside #run_server instead of
forcing caller to do so.
FIXED UNIT TEST ISSUES!!! \(^o^)/
Load path and configuration setup belong in #startup along with any
required files. DataMapper adapter connections go in #setup. That's
the secret recipe.
Added unit tests for required config.yaml settings.
Added unit tests for Dns::Server public interface.
Moved DM adapter setup into first "test" method.
Since #setup is called between each test, the database table would
otherwise be cleared every time.
Added unit tests for #add_rule.
These represent the first actual tests for the Dns::Server class.