mainline: added log4net into reference folder
mainline: added log4net into reference folder

jmptrader/SuperSocket,kerryjiang/SuperSocket,jmptrader/SuperSocket,chucklu/SuperSocket,mdavid/SuperSocket,ZixiangBoy/SuperSocket,fryderykhuang/SuperSocket,jmptrader/SuperSocket,mdavid/SuperSocket,fryderykhuang/SuperSocket,chucklu/SuperSocket,ZixiangBoy/SuperSocket,mdavid/SuperSocket,chucklu/SuperSocket,fryderykhuang/SuperSocket,memleaks/SuperSocket,ZixiangBoy/SuperSocket,kerryjiang/SuperSocket