Sanitization and better TGUI utilization

- Sanitizes some more things so you can't put HTML into it.
- Utilizes TGUI better to show the user the max they can post.
- Limits some things like circuits so you can't insert 50000 characters.

code/modules/admin/verbs/randomverbs.dm

@@ -86,10 +86,14 @@
 	if (!holder)
 		return
 
-	var/msg = sanitize(tgui_input_text(usr, "Message:", text("Subtle PM to [M.key]")))
+	var/msg = tgui_input_text(usr, "Message:", text("Subtle PM to [M.key]"))
 
 	if (!msg)
 		return
+
+	if(!(msg[1] == "<" && msg[length(msg)] == ">")) //You can use HTML but only if the whole thing is HTML. Tries to prevent admin 'accidents'.
+		msg = sanitize(msg)
+
 	if(usr)
 		if (usr.client)
 			if(usr.client.holder)