Reduce the number of pages scraped for the Hills

This scraper takes forever; their server is ridiculously slow, we have
to hit a page for every application and they seem to have heaps of
DAs. Hopefully this change still gets all DAs but doesn't take so long
PA-460 Add notes about ScraperWiki scrapers with issues

Many of these could simply be logged as tickets rather than polluting
the code with comments but for the moment it seems useful to have
these notes down here with the code