Support for location-based and server-based Bungee teleports

Added the command "/gate setbungeetype [id] [location/server]" to allow
both server-based Bungee teleports (i.e. spawn at last location) and
location -based teleports (i.e. spawn at designated location). Players
entering server-based Bungee gates in vehicles will be removed from
their vehicles.

Also added additional config (conf.json) checks for strings.