fixed support for rectangles when no x,y attributes are specified

defaults to 0,0

svgpathtools/svg2paths.py

@@ -83,8 +83,8 @@ def rect2pathd(rect):
     
     The rectangle will start at the (x,y) coordinate specified by the rectangle 
     object and proceed counter-clockwise."""
-    x0, y0 = rect['x'], rect['y']
-    w, h = rect["width"], rect["height"]
+    x0, y0 = float(rect.get('x', 0)), float(rect.get('y', 0))
+    w, h = float(rect["width"]), float(rect["height"])
     x1, y1 = x0 + w, y0
     x2, y2 = x0 + w, y0 + h
     x3, y3 = x0, y0 + h