Fixed vnc_perf.html

This commit updates vnc_perf.html so that it works with the current
version of noVNC.  It also introduces a utility to convert noVNC session
recordings recorded in base64-mode to binary-mode recordings, since noVNC
no longer supports base64-mode.

Fixes #479.

utils/b64-to-binary.pl

@@ -0,0 +1,17 @@
+#!/usr/bin/env perl
+use MIME::Base64;
+
+for (<>) {
+    unless (/^'([{}])(\d+)\1(.+?)',$/) {
+        print;
+        next;
+    }
+
+    my ($dir, $amt, $b64) = ($1, $2, $3);
+
+    my $decoded = MIME::Base64::decode($b64) or die "Could not base64-decode line `$_`";
+
+    my $decoded_escaped = join "", map { "\\x$_" } unpack("(H2)*", $decoded);
+
+    print "'${dir}${amt}${dir}${decoded_escaped}',\n";
+}