Do not crash on None in signal handler

Closes rhbz#1005472

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Petr Kubat <pkubat@redhat.com>
Fix issues found by new pylint

Closes #30

Signed-off-by: Jakub Filak <jfilak@redhat.com>
Signed-off-by: Petr Kubat <pkubat@redhat.com>
Do not change old selection upon reloading

Closes #29

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