User manual: Add text explaining delete of photos from the Photos tab

This text addresses issues about the deletion of photos using the
Photos tab. It also deals with interpreting information regarding
photos laocated on an external drive that is not connected to the PC.

Signed-off-by: Willem Ferguson <willemferguson@zoology.up.ac.za>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Update russian translation of the user manual

Aligned with english version  150783f180f

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Reload the dive list after accepting changes

So far we only did it when we added a dive or modified a manually added
dive. But the reality is that an edit of any dive could cause changes that
require the dive list to be reloaded.

Fixes #698

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>