Before this this commit the terminal strip editor couldn't only work on
the first project opened into this editor, all other project opened
after couldn't be edited.
This is now past, terminal strip editor can now edit every project open
in QElectroTech.
Fix crash when :
1°-Open a project with terminal strip and open the terminal strip editor
2°-Close the terminal strip editor and the project (keep qelectrotech
open).
3°-redo step 1 and click on an item in the tree at left of the window,
qet crash.
Qet don't crash anymore but the terminal strip editor continue to work
with the terminal strip of the first opening (exactly the pointer of the
terminal strip) who don't exist anymore. Need more work.
Since this commit, the terminals can't be moved from the tree widget,
instead we need to use the "move in" widget to move one or several
selected terminals in the table view.
