GUI: fixed application form

- Do not move app form down if linker is not present.
- Use "No, thanks" instead of "Cancel" when user is offered to join
  identities on registration form.
Merge pull request #351 from zlamalp/registrar_fix

GUI: fixed application form

- Do not move app form down if linker is not present.
- Use "No, thanks" instead of "Cancel" when user is offered to join identities on registration form.