Known Bugs:


Known bugs in gtk_plot_data:  if the vertices are too far out of 
the clip region, sometimes the data points are clipped out of 
existance, and sometimes not. (vert and horizontal).

-- crash if gtk_plot_data_set_symbol (color is null)

-- fill_area is broken on polar plots

-- need anti-aliased lines
-- need anti-aliases text

--------------
known bugs in gtk_strip_chart:

-- some operations are order dependent: e.g. limits must be
   added only *after* all the strips have been added.  This should be 
   changed to make things order independent.
   (crusors should work in an order-independent way now).

-- One can only add strips to the chart, one cannot remove.  Ditto,
   limts and cursors.  One should be able to remove them.

-- One cannot programmtically reset a limit. (because theres 
   no handle to grab it with).  

-- using date for x axis should be abstracted. Nasty l10n issue

TODO 
----
-- try to make the symbol a triangle instead of a line for the cursors.
-- put a label above a triangle symbol.

