minor corrections, while cleaning up old edit scripts

See merge request !465

update devtools/lines_of_code

See merge request !464

Remove net oriented sample editor

See merge request !463

...which held the position of an item in the GraphicsScene of the net oriented sample editor

still no classes of the net oriented sample editors are removed, only the UI doesn't show it any more

simplify code; remove test code

See merge request !462

this was used as a playground to try out things

Improve layer editor

See merge request !461

Complete editors for interference

See merge request !460

interference functions: disable total particle density edit if the density is defined by the interference function

again manual corrections in response to clang-tidy

See merge request !459