Fix data download bug

[keatonwilson]

In some instances (only noticed for stratification - check all), the specific data being viewed is not passed through to the downloadable data.

[jessicaguo]

Checked them all - downloads are working as expected, except that stratification data is categorical and shows up as 1, 2, and 3.

Added somewhat messy wrangling code to turn the data wide, so that the stratification can be converted to a character string.

[keatonwilson]

Closed by #63