Create drawfish2D.cpp

1.StringParser and Mesh are from course note, ignore them.
2.Look at main() function, in which you could know how to draw a fish using 
Mesh fish(x,y,theta,0);
fish.ReadFromFile("ChineseFish.stl");// add your own path of "ChineseFish.stl" but do not change the file "ChineseFish.stl"
fish.Draw()
3.change the path in DrawOneSet() into you own path of these stl file.