improved(?) ConCallback::libxbee_callbackFunction - will now perform better, but is a little less 'safe'
fixed major bug in network server - conValidate() now works correctly
xbee_logTargetSet() and xbee_logLevelSet() now announce their changes
made fileno() cross system compatible
Merge branch 'master' into win32, and added xsys_fileno() for windows