Fix channel password prompt

Add zin param to allow explicit z-index in JS generated dialog boxes.
Give needpass dialog explicit z-index

www/js/callbacks.js

@@ -139,7 +139,7 @@ Callbacks = {
             .css("margin-top", "5px")
             .text("Submit")
             .appendTo(div);
-        var parent = chatDialog(div);
+        var parent = chatDialog(div, '9999');
         parent.attr("id", "needpw");
         var sendpw = function () {
             socket.emit("channelPassword", pwbox.val());

www/js/util.js

@@ -2097,11 +2097,20 @@ function waitUntilDefined(obj, key, fn) {
     fn();
 }
 
-function chatDialog(div) {
+/*
+    God I hate supporting IE11
+    https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Default_parameters
+    https://caniuse.com/#search=default%20function
+
+    This would be the ideal:
+    function chatDialog(div, zin = "auto") {
+*/
+function chatDialog(div, zin) {
+    if(!zin){ zin = 'auto'; }
     var parent = $("<div/>").addClass("profile-box")
         .css({
             padding: "10px",
-            "z-index": "auto",
+            "z-index": zin,
             position: "absolute"
         })
         .appendTo($("#chatwrap"));