Handle case of status=*
Sum headaches for each version
Initial attempt at a line of cumulative headaches

Doesn't work yet.
Plot the total headaches on the graph
Plot burnup
Port to area graphs, stack AT on top of done
Add issues failing AT to burnup
Add axis labels
Rotate iteration labels to be visible
Add line name for Scope line
Add linear regressions
Trim empty revisions off the front
Use the whole screen
Add markers for burnup lines