Create Modal Table For Emissions Data for Accessibility

[vkoves]

In investigating the accessibility of the site in issue #13, the one outstanding issue I found was that the US and state emission graphs can't be read by a screen reader (which makes sense, it's an <svg>). Alt text is not going to be sufficient or scalable, so my suggestion is to:

1. Create a table view of the emissions data
2. Make a modal showing this table next to the emissions graphs
3. (Ideally) Create a text summary of the graph, with something like:

Emissions in the US went up from X Gigatonnes in [Start Year (1990)] to a peak of Y Gigatonnes in [Peak Year (2007 for US)] and have declined to Z Gigatonnes in [Current Year]. We project that emissions should go down [D] Gigatonnes per year to reach 0 by 2050.