Remove deprecated CoreWLAN methods

**URGENT 10.9**

According to http://stackoverflow.com/questions/18116861/cwnetwork-security-mode-information most of the methods we used for Airport fiddling have been removed from 10.9 (cannot confirm, haven't tested)

I've gone ahead and removed *most* of the deprecated methods... for now.
I've had to switch to using `CWKeychainCopyPassword()` to get the password for networks, which is marked as deprecated in 10.9. Better than "removed in 10.9", so we've got 2 more versions until it breaks again ;-)