Add missing Perl examples.
Also need full URLs in all Perl requests, not just the relative URIs returned from templates.
Remove superfluous "Params" item.
It is used in only a single API, search, and I wanted a table for them, so just
remove from the other docs.
Document which servers provide each API.
Remove superfluous punctuation.
Make a list.
Document the download API.
Add placeholder pages for all APIs.