Creator's signature for addressbook entry

* Added creator's signature to address book entry.
* Re-factory and improve the merge of them
* Remove entry if has a wrong signature and display a message.
* Hide or show the label of addressbook everywhere.
* Complete test for addressbook methods

Note: review design please.

Fixes  #722
```
 if (!key) throw new Error('[functioname] called without key') 
```
follows our *fail early* policy.