gui: support Enter & 2Click in Preferences list

Related to rhbz#1067123

Signed-off-by: Jakub Filak <jfilak@redhat.com>
gui: apply configuration dialogues changes on Enter key

Related to rhbz#1067123

Signed-off-by: Jakub Filak <jfilak@redhat.com>
gui: close ask dialogues on Enter key

Related to rhbz#1067123

Signed-off-by: Jakub Filak <jfilak@redhat.com>