Add feral hogs to the index

Per #18.
Remove erroneous properties

Per #4.
Validate against "conformsTo," not "schema"

Per #4.
BOVA IDs are strings, not numbers

Sometimes they have leading zeroes.
List the members of a “species” (I use the word loosely) as an array,
not as an object.
Take a first crack at squirrel

This isn’t done—we have no idea of which species is which—but it’s
close.