Fixing various mob attack messages

* span classes instead of \red and \blue
* Replace the bold red color in attack messages for third party with just red.
* Replace "for(var/mob/O in viewers(src, null)) + show_message" stuff by visible_message() proc in.
* Attacks by simple animals and slimes now gives a bold red message for the human target and red message for the other viewers.
* Blob attack message for the target is now bold red. Message added for monkey target.