Enforce the panel visibility on every desktop.

In some cases (slow systems) tint2 renders itself before the WM (in our case openbox) has been fully initialized.
This may cause some weird things, e.g. the panel is visible only on the first desktop.
This workaround ensures that after ~3 seconds the panel sticks on every desktop, by resetting its X property.
Merge branch 'master' into debian
0.22-1