Minor fixes to telecomms/airlocks

This is my first PR to Spessmens, please be gentle. This intends to fix the following bugs:

* ~~**Airlock assembly/electronics duplication when deconstructing airlocks**.~~ This has been fixed recently by Duny.
* **Getting stuck on the same tile as an airlock after being crushed by it**. The `/obj/effect/stop` object created when you get crushed didn't get deleted after being crushed, so you couldn't move (but you could be pulled out). On top of that, if you escaped it and stepped again on the tile you would get stuck again.
* **Inability to fix emagged airlocks crowbaring them**. This bug was introduced on the wire redesign, where the `operating != -1` check went missing.
* **Inability to link/unlink telecomms machinery**.
* **Charred electronics (from emagging) still being functional in some cases**.

Hope I got everything right.