lib: Handle "Class" property updating
lib: Use BluetoothType instead of guint
wizard: Fix PIN debug output arguments

Type and address were swapped.
lib: More debug when setting a device as trusted fails
wizard: Better DisplayPinCode rejection

This is better code.
wizard: More debug for NULL pincodes
wizard: Better debug in pincode_callback()
wizard: Set devices as trusted while pairing

The simple-agent does the same, setting the device as trusted
before returning the PIN code.