restructuring

src/DoubleTank.jl

+using WebIO
+module DoubleTankLab
+using InteractNext, WebIO, Mux, Plots, LabProcesses, LabGUI, Mux, LabConnections#, Blink
+const webio_serve = Main.webio_serve
+include("tankgraphic.jl")
+include("doubletank.jl")
+include("tanklabgui.jl")
+include("tankdemo.jl")
+end