Lots of patches makes the draws to layered view take a long time

This is strange. Try this code (in `/wolfsheep` or something):

    to setup 
      ca
      resize-world -100 100 -100 100
      crt 1
      reset-ticks
    end
    
    to go
      ask turtles [
        fd .1
      ]
      tick
    end

Run it and profile. When you check the profile results, you'll see that the `drawImage` calls in `LayeredView` are taking a really long time. We may want to toss the `LayeredView` altogether, and just position the layers on top of each other.