Add additional checks to secure helper tool.
-- NSXPCListener will not even accept a connection by a user other than the current console user.
-- The users sent in must be the current console user
-- Added invalidation handler to the helper tool, that can be used to initiate the helper tool exit.
-- Added errorHandler to the NSXPCConnection in LGAutoPkgSchedule.m, so we can reset the IBOutlets to previous state on error.