Changes many span classes.

Replaces for(mob in oviewers) show_message()  with visible_message() when possible.

Fixes the absolute pathing in Ninja code.

Fixes facehugger attack messages being bold red for third party (only the first leap message will stay bold red for third party, for better visibility)

Standardizes vomiting message

Fixes mech occupant not receiving any attack messages when the mech is attacked.
Merge pull request #5318 from phil235/MsgFix2

More messages fixed