added stretchy bar to main window
added stretchy bar to main window

bbgw/Klampt,hpbader42/Klampt,krishauser/Klampt,arocchi/Klampt,arocchi/Klampt,arocchi/Klampt,YilunZhou/Klampt,hpbader42/Klampt,YilunZhou/Klampt,bbgw/Klampt,stevekuznetsov/Klampt,krishauser/Klampt,stevekuznetsov/Klampt,YilunZhou/Klampt,bbgw/Klampt,YilunZhou/Klampt,hpbader42/Klampt,stevekuznetsov/Klampt,bbgw/Klampt,krishauser/Klampt,hpbader42/Klampt,krishauser/Klampt,krishauser/Klampt,arocchi/Klampt,stevekuznetsov/Klampt,hpbader42/Klampt,krishauser/Klampt