[MAP] ~20 typo fixes, updated DJ station instruction sheet, replaced missing disposal underneath HoP office door

* Edited arcade.dm: Fixes "Pin ball" typo in arcade machine description
* Edited encryptionkey.dm: Fixes about nineteen typos (#567)
* Edited tools.dm: Fixes "screwwy" typo in screwdriver description
* Edited paper.dm: Updates DJ station instruction sheet in light of the removal of the broadcaster and receiver from the DJ station (#638)
* Edited lib_items.dm: Fixes typo in "unwrenched" in a bookshelf deconstruction step (fixes #527)
* Edited tgstation.2.1.2.dmm: Adds updated DJ station sheet to DJ station, (#638) replaces missing disposal pipe underneath HoP office door (#622).