Slave Stat History Plotting

I wanted to see more stats so I made a simple plot to show some numbers changing over 5 weeks. With 20+ slaves it gets difficult to tell if their devotion is actually going up.

I added a slaveHistory variable to Experimental and everywhere I thought it was relevant.

endWeek.js will store the last weeks data into the new slave.History at the start of the end.

• calls historyChange.js
• May need to add new variables to slave to story (lastWeekAssignment, lastWeekExpenses)
• If these number change before we end the week, it will change the numbers for last week. I think these are minor enough to ignore. If we do anything with the lastWeekAssignment we'll need to write that in.

slaveHistoryGraph.js

• uses a Canvas to plot instead of importing a new plotting module; D3, Plotly... Only problem is that it automatically scales the text. It’s readable on my mobile device at 16px.

Other Notes:

1. With 5 weeks of income, we could consider changing the Underperforming Slaves to use a 5 week rolling average instead of just the previous week. Should probably track the reputation/dollar as well.
2. What is the preferred way to get the default font style? I couldn't find the magic to apply the font correctly into the canvas text.