Xenomorph fixes, typing indicator fix, several incidental tweaks.

Fixes:
- Tackle verb does not appear to knock people down on a successful proc.
- Some organs won't transplant back into the host.
- Cortical borer brain organ can be detached but not removed (cannot reproduce)
- 'doesn't normally have an X' doesn't stop the step from proccing attack.
- Items spawn on join irrespective of being accessible via the HUD (ID on aliens, etc).
- Tyler Corbin has separated the alien queen (1)'s with the incision management system. <-- should be brain
- Alien organs create a red blood effect.
- Diona profile movement animation is a bit odd (blocky pixels on the arse end).

Incidentals:
- Removed unused appendix var.
- Removed lungs from xenomorphs, they don't breathe anyway.
- Makes bioprinters impassable.
- Fixes borers being duplicated when removed from husks via implant surgery.
- Only one surgery step can be running on a given patient at any given time. 
- Failing a surgery step due to moving away now gives a message.
- Corrected 'Tajaran' to 'Tajara' en masse since plural names are now in and the inaccuracy was bothering me.
- Uncommented whitelist check for Zhan scarf and added a comment. It was specifically added for Zhan, leave it alone.

It was specifically added by request of the cat maintainer as a Taj-specific item (as well as being sprited using the cat as a template). If you want a general headscarf you can add one.