Decrease tolerence for moving axes
Fix bug report Wed, 13 Nov 2013 17:44:32 +0000

Traceback (most recent call last):
  File "veusz/windows/plotwindow.pyc", line 900, in checkPlotUpdate
  File "veusz/document/doc.pyc", line 430, in paintTo
  File "veusz/widgets/root.pyc", line 111, in draw
  File "veusz/widgets/page.pyc", line 353, in draw
  File "veusz/widgets/widget.pyc", line 309, in draw
  File "veusz/widgets/grid.pyc", line 414, in draw
  File "veusz/widgets/grid.pyc", line 375, in _drawChild
  File "veusz/widgets/graph.pyc", line 273, in draw
  File "veusz/widgets/plotters.pyc", line 172, in draw
  File "veusz/widgets/bar.pyc", line 548, in dataDraw
  File "veusz/widgets/bar.pyc", line 455, in areaDrawStacked
IndexError: index 0 is out of bounds for axis 0 with size 0