errorbars on decade rowChart

[KatiRG]

Equation:

alpha * 2 * sqrt( (k/N) * (N - k) )

where:
alpha = fudge factor to account for fact that events are not indep. Use alpha = sqrt(5)
k = analogue count in the decade
N = number of days in the decade

For code, see: http://jsfiddle.net/gordonwoodhull/yrugrbhq/17/
Errorbars do not clear automatically, so need to add chart.selectAll('.errorbar').remove()