The hit counter now counts only rss.chat

When the app starts up it registers a hit, so there's a running count of how much rss.chat is used. But everyone running their own server uses this same client -- and their visitors were being counted too, hits arriving from servers that aren't ours. Now the client checks which server it's serving and only counts when it's on an rss.chat domain. If you run your own install, your traffic is yours alone. Fixed by DW. (Client v0.6.12.)