Saves from having to check isset() and all that junk.
Uses dot separated config paths like the database.
Usage:
Config::get('install_dir')
Config::get('memcached.enable', false)
Config::getDeviceSetting($device, 'retries', 'snmp', 5)
Config::getOsSetting($device, 'nobulk')
Config::set('poller_modules', array())
