Area selecting procedures

[hnOsmium0001]

Currently all operations can only be done with one procedure at a time. For batch operations such as moving a whole command graph, able to operate on multiple procedures at the same time would be very handy.

Even though this might require rewriting some of the operation logic such as how copying works, I think this is worth the price in the long run.

• Extract copy/paste/cut logic from FlowComponent into some kind of ProcedureOperation class
• Define the multi-procedure information format
• Area selection handler in EditorPanel, including a list of all selected procedures