fixed freqresp to new controlsystems version

src/BallAndBeam.jl

@@ -173,7 +173,7 @@ function fbdesign(G::AbstractMatrix, polevect, zerovect, gain)
 	ω = Float64.(G[:,1])
 	pzv = isempty(zerovect) ? 1 : prod(abs.(zerovect))
 	sysFB = ss(zpk(zerovect,polevect,gain*prod(abs.(polevect))/pzv))
-	C = Number[ω freqresp(sysFB, ω)[1][:]]
+	C = Number[ω freqresp(sysFB, ω)]
 	L = Number[ω G[:,2].*C[:,2]]
 	T = Number[ω L[:,2]./(1+L[:,2])]
 	sysFB,L,T,C