Added Matlab test script

Author: Jason Bluhm

test.m

@@ -0,0 +1,8 @@
+% This tests whether the impulse_response.m function works
+
+fs=10;
+t=-1:1/fs:1;
+x=cos(2*pi*t);    % input signal
+y=3*cos(2*pi*t);  % output signal
+[h,t]=impulse_response(x,y,fs);   % we expect the impulse response to be
+amplitude=(1/fs)*trapz(h)         % a dirac delta with amplitude 3