added some minor feature to channels

- clean up of channels old (> storeperiod) cache file downloads called at rsglobal shutdown

- added extrafilehash and extra-remove to rschannels, so it chooses appropriate way to add files (correct book-keeping)
   - added extra files not copied to chan dir if over 100mb (high overhead)
- added limit to channels auto-download (1gig)




git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@2866 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/rsserver/p3face-config.cc

@@ -166,8 +166,8 @@ void    RsServer::ConfigFinalSave()
 
 void RsServer::rsGlobalShutDown()
 {
-
-
+	// TODO: cache should also clean up old files
+	mChannels->cleanUpOldFiles();
 	ConfigFinalSave(); // save configuration before exit
 	mConnMgr->shutdown(); /* Handles UPnP */
 }