Adds ability for players to ignore other players. (#1539)

Players can now choose to not receive messages in OOC and deadchat from specific players, with the Ignore verb, or in the global preferences tab.
Ignores can be reverted with the Unignore verb, or with the global preferences tab as well.
This has no effect on IC chat. LOOC is also exempted from this.  Admin messages cannot be blocked.

code/modules/client/preference_setup/global/05_ooc.dm

@@ -0,0 +1,38 @@
+/datum/category_item/player_setup_item/player_global/ooc
+	name = "OOC"
+	sort_order = 5
+
+/datum/category_item/player_setup_item/player_global/ooc/load_preferences(var/savefile/S)
+	S["ignored_players"]	>> pref.ignored_players
+
+
+/datum/category_item/player_setup_item/player_global/ooc/save_preferences(var/savefile/S)
+	S["ignored_players"]	<< pref.ignored_players
+
+
+/datum/category_item/player_setup_item/player_global/ooc/sanitize_preferences()
+	if(isnull(pref.ignored_players))
+		pref.ignored_players = list()
+
+/datum/category_item/player_setup_item/player_global/ooc/content(var/mob/user)
+	. += "<b>OOC:</b><br>"
+	. += "Ignored Players<br>"
+	for(var/ignored_player in pref.ignored_players)
+		. += "[ignored_player] (<a href='?src=\ref[src];unignore_player=[ignored_player]'>Unignore</a>)<br>"
+	. += "(<a href='?src=\ref[src];ignore_player=1'>Ignore Player</a>)"
+
+/datum/category_item/player_setup_item/player_global/ooc/OnTopic(var/href,var/list/href_list, var/mob/user)
+	if(href_list["unignore_player"])
+		if(CanUseTopic(user))
+			pref.ignored_players -= href_list["unignore_player"]
+			return TOPIC_REFRESH
+
+	if(href_list["ignore_player"])
+		if(CanUseTopic(user))
+			var/player_to_ignore = input(user, "Who do you want to ignore?","Ignore") as null|text
+			if(player_to_ignore)
+				player_to_ignore = sanitize(ckey(player_to_ignore))
+				pref.ignored_players |= player_to_ignore
+			return TOPIC_REFRESH
+
+	return ..()