Exception while changing pad shape from circle to square [ crash ]

Traceback (most recent call last):
  File "rzn/ui/glwidget.py", line 54, in paintGL
  File "rzn/view.py", line 293, in on_draw
  File "rzn/view.py", line 210, in on_draw
  File "rzn/render/renderer.py", line 172, in render
  File "rzn/render/renderer.py", line 116, in _renderSelection
  File "rzn/render/renderable.py", line 253, in draw
  File "rzn/render/renderable.py", line 98, in pad_gen
Exception: unhandled shape

Fixed in v0.7.1