postgres numeric -> ocaml string

[bruce-ricard]

This doc (http://pgocaml.forge.ocamlcore.org/pgoctut.pdf) states that numeric should be parsed into an ocaml float type, but I get strings in my code. I have an integer and numeric columns, and when I run a SELECT from pgocaml they respectively return an integer (as expected) and string (I would expect a float here).