Translate user manual into Russian

Translation is almost done section-by-section for easier tracking of
further changes to master copy. It probably needs some re-styling but
not for 4.2.

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
User manual: fix dive depth wording

Picture shows dive to 20m in 30 min. so text should state the same

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Minor corrections to user manual

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Get the Russian manual installed as well

This way it will end up in the installers, too.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Planner: show mean depth

Almost invisible, mostly looking like an odd bug in the profile code,
there was a tiny red line at depth 0 in the planned profile. Turns out
that was the missing mean depth. We didn't populate enough data in the
dive computer of the dive we generated from the plan (and the length of
the depth line was incorrectly determined by the duration of the dive
instead of the duration stored in the dive computer).

Fixes #570

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