Convert the existing regression test scripts for the various optional

PLs to use the standard pg_regress infrastructure.  No changes in the
tests themselves.  Andrew Dunstan

src/pl/plpython/sql/plpython_schema.sql

@@ -0,0 +1,42 @@
+
+CREATE TABLE users (
+	fname text not null,
+	lname text not null,
+	username text,
+	userid serial,
+	PRIMARY KEY(lname, fname) 
+	) ;
+
+CREATE INDEX users_username_idx ON users(username);
+CREATE INDEX users_fname_idx ON users(fname);
+CREATE INDEX users_lname_idx ON users(lname);
+CREATE INDEX users_userid_idx ON users(userid);
+
+
+CREATE TABLE taxonomy (
+	id serial primary key,
+	name text unique
+	) ;
+
+CREATE TABLE entry (
+	accession text not null primary key,
+	eid serial unique,
+	txid int2 not null references taxonomy(id)
+	) ;
+
+CREATE TABLE sequences (
+	eid int4 not null references entry(eid),
+	pid serial primary key,
+	product text not null,
+	sequence text not null,
+	multipart bool default 'false'
+	) ;
+CREATE INDEX sequences_product_idx ON sequences(product) ;
+
+CREATE TABLE xsequences (
+	pid int4 not null references sequences(pid),
+	sequence text not null
+	) ;
+CREATE INDEX xsequences_pid_idx ON xsequences(pid) ;
+
+