Added configuration class.
Added Configuration::Destination.
Added Configuration::NotificationService.
Filled in Publisher::Configuration with loading from configuration hash.
Updated ConfigurationReader to load from configuration object instead of hash.
Moved configuration support out into module.
Remove clunky configure method from publisher instance and load configuration in initialize.
Updated README.
Merge pull request #31 from payrollhero/add-proper-publisher-config

Add proper publisher config