Added flag-groups that can contain editable and not editable WorldGuard flags.
Every flag group has one flag-set for regions that are sold and one for regions that are available
Added flag editor that can be used by users to edit editable flags for their regions via GUI interface.
Added SignLinkMode blacklist. WorldGuard regions can be added to a list that is located in the config.yml. Regions that have been added to that list will be ignored by the SignLinkMode.