Addressbook: Add initial support for signatures in subscriptions

...addressbook/java/src/net/i2p/addressbook/AddressBook.java

...ressbook/java/src/net/i2p/addressbook/ConfigIterator.java

apps/addressbook/java/src/net/i2p/addressbook/Daemon.java

...ddressbook/java/src/net/i2p/addressbook/HostTxtEntry.java

...dressbook/java/src/net/i2p/addressbook/HostTxtParser.java

...ok/java/src/net/i2p/addressbook/SubscriptionIterator.java

...va/src/net/i2p/client/naming/SingleFileNamingService.java

history.txt

router/java/src/net/i2p/router/RouterVersion.java