revert GuestPass to extend plain Permission

BasicPermission was causing problems by thinking that different GuestPass
instances were the same and using only one.
Could probably be resolved by fiddling with names,
but we don't really need it.
skip security checks if we are not the system-installed security manager (relates to issue #5)

This hides the privileged actor from subclasses
unless the caller had sufficient privileges to set up the system security manager
(in which case they own the system anyway).
add BeforeClass checks to ensure that permission system is initialized properly