Continued:

- deleteContactData() does now throw ContactNotFoundException, if the given
  contact was not found but method was invoked
- renamed getAllContacts() -> allContacts() as this is no pure getter
- renamed getEmailAddressList() -> allEmailAddresses() to follow naming
  convention: no getter and no need for "List" suffix, "all" prefix says it

Signed-off-by: Roland Häder <roland@mxchange.org>