sql.py: put_table(): Inserting new rows: Use insert_select()'s (mk_insert_select()'s) new ignore option to ignore duplicate keys

sql_gen.py: to_name_only_col(): Consider any non-table column, including NamedCol, to be already name-only. This fixes a bug in sql.mk_insert_select() where the value of a NamedCol was removed by to_name_only_col() even though it was needed.

sql.py: mk_insert_select(): INSERT IGNORE: Use an EXCEPTION block for each individual row because "When an error is caught by an EXCEPTION clause, [...] all changes to persistent database state within the block are rolled back." (http://www.postgresql.org/docs/8.3/static/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING). Documented that cursor stays at current position in spite of automatic ROLLBACK on EXCEPTION.

sql.py: mk_insert_select(): INSERT IGNORE: Use RETURN QUERY on the insert query instead of RETURN NEXT on a local var to forward the RETURNING value

sql.py: mk_insert_select(): INSERT IGNORE: Support RETURNING clause. Always return something to set the correct rowcount.

sql_gen.py: Use an as_*() function instead of manually checking the type wherever possible

sql.py: mk_insert_select(): INSERT IGNORE: Added duplicate key handling by using EXCEPTION block to catch unique_violation

sql.py: mk_insert_select(): INSERT IGNORE: Fixed bug where user-defined types were not supported correctly, by referencing the column's type directly in PL/pgSQL instead of retrieving it from the information_schema. Use a row variable of the output table's row type to store the select query data, so that you don't need to create a separate local var for each output column.

import.stats.xls: Changed \/row (ms)" to "ms/row"

sql.py: mk_insert_select(): INSERT IGNORE: Used typed vars to store each column of the select query because the select query's column names are not known, so it would be unknown which record var column to use for each output column. (Add types so there are no unknown-type values that PostgreSQL will say can't be cast.)