Manually merge printTotals from Aleh's fork.
Implement inverted functions for the case where we have negative stacked graphs, but wish the legend values to be the inverse.

Also, fix safeMap that was not actualy doing a safeMap.
Merge branch 'rfc/render_print_totals' into appnexus_rollup
Merge branch 'rfc/render_inverse_legend_values' into appnexus_rollup