Public access to bounds of a GridDataSource object about chaco

[timdiller]

I found an undocumented implementation that looks like this, assuming a self.plot instance of Plot:

def update_axes(self, new_xbounds, new_ybounds):
    renderer = self.plot.plots[0]
    renderer.index.set_data(new_xbounds, new_ybounds)
    self.plot.invalidate_and_redraw()

I don't think this pattern is in the documentation.

[timdiller]

In fact, the only necessary line is this, for the record:

renderer.index.set_data(new_xbounds, new_ybounds

Closing the issue, since this is really an issue of documentation- #161