Only show the replies button if replies exist.

This simplifies the first time user experience a little

webapp_headerbuttons.py

@@ -7,6 +7,7 @@ __email__ = "bob@freedombone.net"
 __status__ = "Production"
 
 
+import os
 import time
 from datetime import datetime
 from happening import todaysEventsCheck
@@ -87,6 +88,10 @@ def headerButtonsTimeline(defaultTimeline: str,
             '"><span>' + htmlHighlightLabel(translate['DM'], newDM) + \
             '</span></button></a>'
 
+        repliesIndexFilename = \
+            baseDir + '/accounts/' + \
+            nickname + '@' + domain + '/tlreplies.index'
+        if os.path.isfile(repliesIndexFilename):
             tlStr += \
                 '<a href="' + usersPath + '/tlreplies"><button class="' + \
                 repliesButton + '"><span>' + \