feat(chat): single chatter query param

Author: IS2511

v2/script.js

@@ -199,6 +199,7 @@ var Chat = {
         lastEmoteBackground: ('last_emote_background' in $.QueryString ? ($.QueryString.last_emote_background.toLowerCase() === 'true') : false),
         reverseLineOrder: ('reverse_line_order' in $.QueryString ? ($.QueryString.reverse_line_order.toLowerCase() === 'true') : false),
         horizontal: ('horizontal' in $.QueryString ? ($.QueryString.horizontal.toLowerCase() === 'true') : false),
+        singleChatter: ('single_chatter' in $.QueryString ? $.QueryString.single_chatter.toLowerCase() : ""),
         ttsReadsChat: false,
         emotes: {},
         badges: {},
@@ -2590,6 +2591,11 @@ var Chat = {
                                 }
                             }
 
+                            if (Chat.info.singleChatter) {
+                                if (Chat.info.singleChatter !== nick.toLowerCase())
+                                    return;
+                            }
+
                             Chat.write(nick, message.tags, message.params[1]);
                             return;
                     }