[refactor] Altered the schema of test runs so that default values are 0 and not NULL {{err:51a12353b1e67e4a5f0003a2}}
[refactor] Used Gchart :bg parameter rather than shoveling transparent backgrounds onto the URL
[refactor] Replaced manual construction of stacked area graph with StaticChartHelper's new stacked_area_graph
[refactor] Renamed accumulate to stack_sum; extracted accumulate from cumulative_flow_diagram
[improvement] Retina-ified the small pie graphs in the Weekly Report
[refactor] Refactored some more
[skip] Tweaked spacing
[refactor] Extracted StaticChart and subclasses from StaticChartHelper
[refactor] Pulled common temp variables out into query methods on StaticChart and its children
[refactor] Defined the Cumulative Flow Diagram in terms of a Stacked Area Graph, allowing all Area Graphs to be stacked
[refactor] Pulled additional Google Chart details out of temp variable into protected methods