put error formatting in dcplot library
use d3 color scales directly and bypass dc.js "color calculator"

maybe i just don't understand...
latest crossfilter.js

coz dc.js needs it - but also just coz!
allow specifying pie wedge order in dc.js

it was brokenly trying to sort by key (see comments)
add an ordering() parameter
do the sort manually instead of trying to use crossfilter group.order()
access to dataframe attributes
dcplot support for R factors

set the new ordering parameter if the chart's dimension is a factor
the ordering parameter is set to a function which uses the
reverse-map of the levels array
also set the color domain from the factor levels