Demo quiver.py not working

[ku-ya]

Problem Description
Zooming in will ends with the following and blank plot.

Reproduction Steps:

Run the file and zoom in until the plot breaks.

Expected behavior:

Plot disappear if keep zooming in and ends with following trace.

Traceback (most recent call last):
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/qt4/base_window.py", line 202, in paintEvent
    self.handler.paintEvent(event)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/qt4/base_window.py", line 54, in paintEvent
    self._enable_window._paint(event)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/abstract_window.py", line 468, in _paint
    self.component.draw(gc, view_bounds=(0, 0, size[0], size[1]))
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/component.py", line 427, in draw
    self._draw(gc, view_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/component.py", line 779, in _draw
    self._dispatch_draw(layer, gc, view_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/container.py", line 272, in _dispatch_draw
    component._dispatch_draw(layer, gc, new_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/container.py", line 272, in _dispatch_draw
    component._dispatch_draw(layer, gc, new_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/enable/component.py", line 799, in _dispatch_draw
    handler(gc, view_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/chaco/base_xy_plot.py", line 466, in _draw_plot
    self._draw_component(gc, view_bounds, mode)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/chaco/base_xy_plot.py", line 474, in _draw_component
    self._render(gc, pts)
  File "/Users/ktakami/.edm/envs/chaco-dev/lib/python2.7/site-packages/chaco/quiverplot.py", line 80, in _render
    ends = points + self._cached_vector_data
ValueError: operands could not be broadcast together with shapes (0,) (0,2)

OS, Python version:
OSX, Python 2.7

splits from #385