Moves references to dc.renderAll or dc.redrawAll to _chart.redrawGroup & _chart.renderGroup respectively.  More conventional with other charts and allows easier overriding.
Merge master
Allowing setting/chaining of piechart cx and cy
Added tests and changed comments
Created new describe block to set up and break down center positioning tests, reverted main test to defaults
artifacts
add two failing ordinal bar tests
add test for changing number of bars
tweak documentation, fix link
add a couple elasticX tests
fix elasticX and watch manual domain changes

record current domain and compare, do rescale if changed
stack mixin was filtering on current domain even when elasticX
reread ordinal domain when elasticX as well (elastic ordinal)
fix ordinal bar charts

it was the outer padding.
also, set _gap undefined when using padding instead
(start to think about gap versus padding really being modes)

fixes #533
artifacts
indentation
do not create extra title elements on redraw

fixes #597
use `d3.dispatch` for chart events

fixes #531
add test for second listener on event
fix erroneous quarter bucketing

fixes #569
Merge pull request #556
Merge pull request #607