add constraints package for constraint classes

Window.py

@@ -4,15 +4,8 @@ import gtk
 from Sketch import Sketch
 from SketchWidget import SketchWidget
 
-from Line import Line
-from Circle import Circle
-from Connect import Connect
-from XDistance import XDistance
-from YDistance import YDistance
-from Horizontal import Horizontal
-from Vertical import Vertical
-from XFix import XFix
-from YFix import YFix
+from shapes import *
+from constraints import *
 
 class Window:
     def __init__(self, title):

constraints.py

@@ -0,0 +1,8 @@
+
+from Connect import *
+from XDistance import *
+from YDistance import *
+from Horizontal import *
+from Vertical import *
+from XFix import *
+from YFix import *