Fix RDF schema problems with lane_number and species.

Fix RDF schema problems with lane_number and species.

My RDF schema was using the term "species" both for the species
name and a species class -- which doesn't make sense. This
version of the schema introduces a species_name which can
attach either to the Library object or the Species object.

Its still a little inconsistent as I'm using it for both
"common name" and "scientific name". But hey its an improvement.

Also there's a tweak to the library_number type on the library detail
page setting the type to string instead of number, as I decided
it should be treated internally as an opaque identifier.
In theory someone might start naming lanes A,B,C,D or 1T, 1B
(for the top and bottom of a flowcell slide).

Finally I decided that the gel_cut should be of type integer,
yes decimal is the "more general type" but I'm using integer in
my sql schema so its only going to return integers.