Mob inside something can now see visible_message()'s

* Mob inside something can now see visible_message. 
* Fixes being able to see visible_message w/o seeing the src of it (happened when the src could see us but not the other way around), you no longer see visible_message from mobs inside closets for example(unless the proc has an audible blind_message argument then you hear that instead).

* Fixes pAI being deaf. The mob is back in the paicard and should be able to hear sounds, visible_message, speech, audible_message. This should fix #5834 , #6045 , #5729 , #2947 , #5759 , #810 and #99. Probably fixes similar problem with shade inside soulstone not seeing visible_message().
* Removing some no longer needed instances of occupant_message() in mecha code and adding a bold red  "taking damage" message.
* Fixed some typos and span class here and there.
* Removed some duplicated code from tools/tools.dm