gigamonkey/gg — pull request #19 by n8agrin (2012-12-26 20:23:16+00:00)
Title: Initial commit for positioners, included an Identity and Stacked positioner

Because positioners may add attributes to data objects that affect
the calculation of scale domains, the logic for calculating the domain has been
moved to the positioner objects.

Note this is a first pass and I'd appreciate feedback on the general
implementation. Of particular note is the fact that only the line geom
currently supports stacking and other geoms will require some effort to be made
compatible. Also note the specialized scale method now present in the Area and
Line geoms suggesting a more generalized version may be more appropriate.