Cleanup how new data is added to better conform to update tutorial

http://bl.ocks.org/mbostock/3808221
Re-arrange

Do need display_group_all because otherwise the new circle will not have
any forces acting on it. More accurately they try to act on it but are
not able to resulting in tons of NaN errors.
Remove the $ from amount in data
Not using old version of d3
Add separate by groups function

Still need a way to specify the title based on the grouping type.
Also need to fix ed case displaying with x=0