Fixes Setting the dive-location via the map.

This patch adds a context menu to set the dive location
via the globe, being the dive with a coordinate or not.

It also fixes setting the dive location on edit mode.

Fixes: #315

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Removed The button box from mainwindow, buttons are now on the message.

The button box on the bottom of the window made it a bit cluttered
on small screens, this patch uses the window of the MessageWidget
to show the butons - this way less space is used and things are better
spaced on screen.

Signed-off-by: Tomaz Canabrava <tcanabrava@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Make the message when editing a dive fit better

This should keep the message widget visible without horizontal scroll bar,
even on fairly small screens.

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