More control over size histogram

[afmagee42]

Resolves, more or less, #38 by giving users control over what they want the histogram to show. Users can now toggle between cumulative sizes and sizes in specific generations for any generation simulated.

Bonus out-of-scope bug fix: app.render_percents() was rounding wrong.

[swo]

A bunch of small thoughts:

• I think it's easier to have the plot options next to the "Advanced options"? I like the sidebar having all the controls, and the main window being just results displayed
• Rather than changing the text above the plot (to adapt for # of generations and cumulative vs. not), I think it would be easier to have that be the x-axis title of the plot itself. Fewer places to look
• Weirdly, the altair plot doesn't break at integers. If this is easy to fix (or you think is worth breaking off into another issue that I tackle), we could look into it.
  

[afmagee42]

Weirdly, the altair plot doesn't break at integers. If this is easy to fix (or you think is worth breaking off into another issue that I tackle), we could look into it.

The breaks on these altair histograms have annoyed me since #32 but I think better breaks is a follow-up issue, including:

• Having 0 not be it's own category means you can't see the extinct generations separately from the small ones
• Should we just show every integer value in the range?
• Should we try to keep ranges comparable across all possible subsets here?

Rather than changing the text above the plot (to adapt for # of generations and cumulative vs. not), I think it would be easier to have that be the x-axis title of the plot itself. Fewer places to look

I previously tried an altair title, and it was both too long (got chopped off) and mucked up the size of the displayed histogram. Now trying it as an x axis label, I see it merely leads to a truncation issue. If we can workshop a shorter (looks like 65 characters or less) and equally clear option, I am game for this.

• "Number of infections in generation G" seems clear for the one, and fits
• "Cumulative infections in generations up to and including" is just too long for the other

[swo]

• "Cumulative infections in generations up to and including" is just too long for the other

"Cumulative infections through generation"?

[swo]

Amazing. It even has a test!