Introduced bindings again for dealing with encryption and decryption of secrets

Secrets are not actually decrypted at the moment. Need to add crypto calls in next commit.
Removed menu entries which we will not need
Started using bindings for length and series

I wanted to avoid this initially, but bindings simplify code a lot when you need to keep two fields in synch. This was less of a problem when I only had a label and not a textfield for length and series.
setNilValueForKey: was important to get right otherwise removing all numbers in textfield would cause exception.
added not working help
Got unit tests to compile rething TLLogin

We probably don’t want TLPasswordGenerator to manage TLLogin arrays. That makes it unclear what it actually does. Secondly it is better that generating a password creates a TLLogin object, then all the relevant data which belong together is put together. This reduces chance of screwing up and bundling passwords with the wrong username and target.
store all generated passwords