add ConnectMode class

SketchWidget.py

@@ -25,6 +25,7 @@ class SketchWidget(object):
                 'select': SelectMode(),
                 'line': LineMode(),
                 'circle': CircleMode(),
+                'connect': ConnectMode(),
                 }
         self.mode_name = 'select'
         self.mode = self.modes[self.mode_name]
@@ -605,3 +606,10 @@ class CircleMode(Mode):
 
     def get_cursor(self):
         return 'crosshair'
+
+class ConnectMode(Mode):
+    def get_cursor(self):
+        return 'crosshair'
+
+    def do_motion(self, sw, x, y):
+        sw.update_hover_snap_point(x, y)