Repath a bunch of things to /mob/abstract childtypes (#4111)

* Repaths eyes, observers, dview, and new_players to /mob/abstract subtypes.

* Adds /mob/abstract, a base type for 'abstract' mobs that aren't meant to be directly affected by the game world.

code/modules/client/preferences.dm

@@ -246,7 +246,7 @@ datum/preferences
 /datum/preferences/proc/process_link(mob/user, list/href_list)
 	if(!user)	return
 
-	if(!istype(user, /mob/new_player))	return
+	if(!istype(user, /mob/abstract/new_player))	return
 
 	if(href_list["preference"] == "open_whitelist_forum")
 		if(config.forumurl)

code/modules/client/preferences_toggles.dm

@@ -78,11 +78,11 @@
 	prefs.save_preferences()
 	if(prefs.toggles & SOUND_LOBBY)
 		src << "You will now hear music in the game lobby."
-		if(istype(mob, /mob/new_player))
+		if(istype(mob, /mob/abstract/new_player))
 			playtitlemusic()
 	else
 		src << "You will no longer hear music in the game lobby."
-		if(istype(mob, /mob/new_player))
+		if(istype(mob, /mob/abstract/new_player))
 			src << sound(null, repeat = 0, wait = 0, volume = 85, channel = 1) // stop the jamsz
 	feedback_add_details("admin_verb","TLobby") //If you are copy-pasting this, ensure the 2nd parameter is unique to the new proc!
 
@@ -224,4 +224,4 @@
 
 	prefs.toggles_secondary ^= SAFETY_CHECK //Held in Parallax because we don't want to deal with an SQL migration right now.
 	prefs.save_preferences()
-	src << "You will [(prefs.toggles_secondary & SAFETY_CHECK) ? "no longer" : "now"] fire your weapon on intents other than harm."
+	src << "You will [(prefs.toggles_secondary & SAFETY_CHECK) ? "no longer" : "now"] fire your weapon on intents other than harm."