Added the skeleton for the Ruler Item,

The ruler will deliver the Time and the Depth, later.
it should be vertical or horizontal, and will have
ticks

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added a 2 Ruler Items, Time and Depth.

The ruler items are needed so I can get the correct
coordinates of the planned dive. This is a very
rudimentary ruler and it needs a bit of love, but
it already gives me something to work on.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added the code to set the Depth / Time on the user Handlers.

Added the code to set the Depth / Time on the user handlers,
I think this finishes the difficult part. ( well, not really )
the depth and time is being set when handler is added or moved,
but as soon as the deco calculations enters on the code, the
handlers will need to be repositioned - and this code is not ready
yet.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added text to the rules so the user knows what's happening at that point.

Added text to the rules, so the user knows what's happening at that point
The text will move left / right ( for time ) and up / down ( for depth )

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Restore the original color of the Handler as soon as mouseRelease.

Restore the original color of the handler as soon as mouseRelease,
also a bit of code cleanup.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Make skeleton of 'create_deco_stop'.

This is a skeleton of 'create_deco_stop' plus a bit of
code cleanup. I'v commented the create_deco_stop so that
the other developers can help me a bit here - since I don't
know too well the internals of subsurface. In the original
GTK code - a new dive was created every time a user changed
something on the dive, I don't know if this will be needed,
I jusst need two things: the correct time of dive calculated
by the app, and the points to put the decompression lines.

The usability of the widget right now is 'ok', nothing to
be proud of, it's ugly as hell too, and the Rules are in
the wrong position ( they are 'inside' the area where
the lines are being drawn, but htis is easily fixable. )

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>