* fix: ping fails on servers that don't set PATH in cron
Find the full path to fping and persist it in the database.
Adds the ability to persist settings with Config::set()
* Add ability to set webui settings.
No display of for paths, because it would be inconsistent.
* refactor: speed up is_valid_port()
Convert is_valid_port to Config
Several Config optimizations
Update documentation
* fix getCombined() when os key is not set, but global is.
Add more tests
* feature: Allow ignore_mount, ignore_mount_string, ignore_mount_regex at OS level
* Change the storage settings to override global instead of merge.
Add documentation
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())
