xNES: avoid sigma overflow
xNES: avoid sigma overflow

multidis/BlackBoxOptim.jl,multidis/BlackBoxOptim.jl,JuliaPackageMirrors/BlackBoxOptim.jl,JuliaPackageMirrors/BlackBoxOptim.jl,tkelman/BlackBoxOptim.jl,JuliaPackageMirrors/BlackBoxOptim.jl,multidis/BlackBoxOptim.jl,tkelman/BlackBoxOptim.jl,tkelman/BlackBoxOptim.jl