[Kst] more healpix/matrix discussion

[Theodore Kisner]

Nicolas,
  thanks for the feedback:

> I surely missed something, but why would the datasource need to know
> data ranges (xmin, xmax, ymin, ymax) ?

my thought was that the datasource might return different Z-values depending 
on the X/Y range.  For example if the returned matrix is a projection.

I've gotten a bunch more feedback off-list, and I think the bottom line is 
this:  nothing is going to happen until there is a general agreement on what 
design we are shooting for in terms of matrix support.  Also George is 
already working on KstViewObjects, which will eventually provide the 
"plotsource" plugin format that will make life easier.

George also pointed out that since datasources can be compiled separately from 
kst, there is no reason to delve into the politics of including them in the 
main source tree.

cheers,

-Ted