Homepage layout overhaul

- Pulled each viz section into two parts -- intro and viz itself -- to give breathing room. We had too much info crammed into screen space.
- Matched style of new work to already-existing styles to bring us closer to the nirvana of site-consistent look-and-feel.
- Added footnote text to map as per ONRR team. It is ready for user testing now to see what further info, if any, is desired.
- Shortened text snippets in sectors viz to simplify that section. There was too much competing for user's attention there.
- Added ascii code ellipses instead of dot dot dot, which is great
- Edited and clarified intro text in several places to bring it more in line with discussions I've had with the ONRR team
- Increased size of map. Now shows bits of Alaska which should help users know that there is info up there, too.
- Changed order of infographics -- map got moved to the middle as it seems more appropriate to keep scrolling down to finer and finer levels of detail.
- Edited intro text on the initial splash to better entice to scroll.
- Changed the way the full-page images are coded to improve scalability