Adding support for more address book API calls and an 'unread' inbox

commit 188be43 resolves #12 

1. convert all tabs to spaces
2. add support for listaddressbookentries and deleteaddressbookentry
3. updates to generating version 4 addresses

commit 6cff812 resolves #13 

1. add support for an "unread" view of the inbox
2. messages are marked as read when read unless user asks to keep unread
3. added "secret" commands to mark all messages as read or unread