Created a method to check if calculations should take place.

Created a method to check if calculations should take place
taking into consideration what changed on the model. if the
model changes *everything*, them, all calculations should
be done, but if just some of the columns of the model are
changed, only those columns should trigger an visual update
on the items.

In theory this patch looks right, but something is wrong (
calculations are not being made. ), so I'll commit this any
how, and fix on the next commit.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Optimizations and fixes on the new profile.

This patch optimizes a few items when hitting the
'save preferences' dialog, since when a preference is
modified, all the items try to reload their visual
based on wether a preference changed or not, the correct
code for 'hey, my pref changed, let's update' needed
to be done.

now the axis will only set a new maximum if it's different
from the old one ( and thus, going to a new dive with
the same maxdepth or maxtime as the old one will not touch
their axis, not triggering gratuitous animations. )

also, the 'incr by 3m' was not being called - it seems
that our 'syncsettings' method is not storing things on
the 'prefs' global var. I added just for the incr by 3m
case, but it's something that we need to check later.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Fix hiding the tissues when user set 'show ceiling' to false.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Added Mouse based Zoom / Movement.

This patch uses the same code that lubomir used on the
old profile. It strangely didn't worked - most probably
because the scene has a fixed width() and height() of
100. the zoom works, and the movement works, but only
on the 100 first pixels of the profile.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>