reflect PG custom types besides ENUM / support composite types

Issue #2450 new
Michael Bayer
repo owner created an issue

this would expand upon _load_enums() in postgresql/, so that any kind of custom type is recognized during reflection. We'd likely have to create some kind of "ad-hoc" type that is declared like this:

from sqlalchemy.dialects.postgresql import TYPE
Column("mycolumn", TYPE("MY_CUSTOM_TYPE"))