ifstate feature: persistent state, fsm correction with ifup, ifdown, ifcheck corrections

This pull request consists of mainly ifstate implementations.

+ Small wireless schema fix to avoid annoying error message
+ ifcheck return codes tweak (bogus), and error message correction (not bogus)
+ FSM corrections (mainly needed because of previous patches)
+ ifup, ifdown better handling of non-configured or persistant interfaces.

Please review.

(I have tested it quite extensively, but this one requires definately much more tests)