README.md: add FAQ "my package didn't show up yet"
lib/debci/html/packagelist.erb: Show a link to every suite/architecture a package is failing
debci-generate-html: Check for an empty data directory

On a new setup of debci, running debci-generate-html
with an empty data directory would cause a crash.
lib/debci/html/packagelist.erb: Clean up the failing suite/architecture link code