Added ( finally ) the code to reduce depth on the planner

Added the code to reduce depth on the planner. Depth
cannot be lower than 40m and it also won't let the
user reduce if there's any point on the 'reduced' area.
the icon is ugly - we need an artist.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added button to reduce dive time on the planner.

Added a button and a method to reduce time on the dive
planner. The dive planner will not reduce below deco-time
and it will also not reduce below TIME_INITIAL_MAX.

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

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added the current gas used on the planner

Added the current gas used on the planner, now it's a matter
of choosing the new gas, that will be done in the next commit.e

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

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added a missing #UNDEF

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Added the possibility to choose gases  in the planner.

Added the possibility to choose gases in the planner,
now the user should click on the name of the gas, a
popup window will appear, asking the user to choose
what gas he wants for that ascent / descent.

now we need to hook that up with the createDecoStops
method that calculates the decompression.

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