Quote picture file names when saving XML

Fixes #775

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Update user manual figures: Ubuntu to Fedora

Replace four more figures.
Replacement complete up to end of section:
Import data from dive computer.

Signed-off-by: willem ferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>