FakeVim: Show command output in new editor instead of dialog

Task-number: QTCREATORBUG-11598
Change-Id: Ifff5a7ffbece93d21a0e688f4f3085d87d9373da
Reviewed-by: Lukas Holecek <hluk@email.cz>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>