Histogram level editor crash

[sampsonbryce]

Moving a slider so that it is == to another slider gives:

/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/numpy/core/_methods.py:117: RuntimeWarning: invalid value encountered in true_divide
  ret = ret.dtype.type(ret / rcount)

and if you continue moving the last slider to == more sliders: '

Traceback (most recent call last):
  File "/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/CDAT_GUI-0.1-py2.7.egg/cdatgui/editors/level_editor.py", line 55, in update_levels
    self.canvas.update()
  File "/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/CDAT_GUI-0.1-py2.7.egg/cdatgui/cdat/vcswidget.py", line 59, in update
    self.canvas.update()
  File "/Users/sampson9/Projects/uvcdat/Packages/vcs/vcs/Canvas.py", line 1044, in update
    return self.backend.update(*args, **kargs)
  File "/Users/sampson9/Projects/uvcdat/Packages/vcs/vcs/VTKPlots.py", line 440, in update
    self.configureEvent(None, None)
  File "/Users/sampson9/Projects/uvcdat/Packages/vcs/vcs/VTKPlots.py", line 319, in configureEvent
    self.canvas.plot(*pargs, render=False, **key_args[i])
  File "/Users/sampson9/Projects/uvcdat/Packages/vcs/vcs/Canvas.py", line 2392, in plot
    a = self.__plot(arglist, keyargs)
  File "/Users/sampson9/Projects/uvcdat/Packages/vcs/vcs/Canvas.py", line 3716, in __plot
    **keyargs)
  File "/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/vcsaddons/core.py", line 142, in plot_internal
    displays = self.plot(slab, template, bg, x, **kwargs)
  File "/usr/local/uvcdat/2.4.0/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/vcsaddons/histograms.py", line 72, in plot
    data_bins = numpy.digitize(data, self.bins) - 1
ValueError: The bins must be monotonically increasing or decreasing