Undo: make weight-deletion an undoable action

This one is a bit more complicated than weight adding, because the
multiple-dive case is not well defined. If multiple dives are selected,
this implementation will search for weights that are identical to the
weight deleted in the currently shown dive. The position of the weight
in the list is ignored.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

commands/command_edit.h

@@ -339,6 +339,18 @@ private:
 	bool workToBeDone() override;
 };
 
+class RemoveWeight : public EditDivesBase {
+public:
+	RemoveWeight(int index, bool currentDiveOnly);
+	~RemoveWeight();
+private:
+	weightsystem_t ws;
+	std::vector<int> indexes; // An index for each dive in the dives vector.
+	void undo() override;
+	void redo() override;
+	bool workToBeDone() override;
+};
+
 } // namespace Command
 
 #endif