Added matlab code samples.

All of these code samples currently are mis-identified in my repositories. I'm
donating them to the cause.

samples/Matlab/Check_plot.m

@@ -0,0 +1,12 @@
+x_0=linspace(0,100,101);
+vx_0=linspace(0,100,101);
+z=zeros(101,101);
+for i=1:101
+    for j=1:101
+        z(i,j)=x_0(i)*vx_0(j);
+    end
+end
+
+figure
+pcolor(x_0,vx_0,z)
+shading flat