Minor GUI L&F.

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
If the keybindings file is not in the target folder, don't crash.

Just use the default keybindings.
Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>
Release v0.10.0

Signed-off-by: Jean-Yves Tinevez <jean-yves.tinevez@pasteur.fr>