rename LobTypeName to PrecLengthTypeName

rename LobMultiplier and LobUnits to PrecMultiplier and PrecUnits
remove support for limit syntax
remove the unreserved keyword list since it isn't useful
tests for row value constructors
tests for table value constructors
tests for query specifications
tests for explicit table
work on tests for setops,order by,offset,fetch and sort specification

tools/Language/SQL/SimpleSQL/Postgres.lhs

@@ -218,7 +218,7 @@ queries section
 >      \  UNION ALL\n\
 >      \    SELECT n+1 FROM t\n\
 >      \)\n\
->      \SELECT n FROM t LIMIT 100;"
+>      \SELECT n FROM t --LIMIT 100;" -- limit is not standard
 
 select page reference