Convert some simple functions from plpgsql to sql

SQL is a faster language to call, and these are very simple functions.

scripts-available/CDB_LatLng.sql

@@ -8,16 +8,12 @@
 --
 
 CREATE OR REPLACE FUNCTION CDB_LatLng (lat NUMERIC, lng NUMERIC) RETURNS geometry as $$ 
-BEGIN 
     -- this function is silly
-    RETURN ST_SetSRID(ST_MakePoint(lng,lat),4326); 
-END; 
-$$ language plpgsql IMMUTABLE;
+    SELECT ST_SetSRID(ST_MakePoint(lng,lat),4326);
+$$ language SQL IMMUTABLE;
 
 CREATE OR REPLACE FUNCTION CDB_LatLng (lat FLOAT8, lng FLOAT8) RETURNS geometry as $$ 
-BEGIN 
     -- this function is silly
-    RETURN ST_SetSRID(ST_MakePoint(lng,lat),4326); 
-END; 
-$$ language plpgsql IMMUTABLE;
+    SELECT ST_SetSRID(ST_MakePoint(lng,lat),4326);
+$$ language SQL IMMUTABLE;