2014-06-06 Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
	* pg_dbms_stats.c: pg_dbms_stats no more causes planner to access
	repeatedly to the tables of pg_dbms_stats for nonexistent saved
	statistics during considering access paths involving tables or
	indexes that don't have their statistics 'lock'ed. This change
	improves the performance especially for light weight (which means
	taking less than a few milliseconds) queries on no-locked
	tables/indexes.

	* pg_dbms_stats.c: Fix a bug potentially causes SEGV crash.
	しました。

	* pg_dbms_stats--*.sql, pg_dbms_stats.control: Now declares the
	right version to the extension framework. ALTER EXTENSION can be
	used to upgrade from the older versions.

2013-11-07 Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
	* Fixed a bug potentially cause SEGV after changing column data
	types on 'lock'ed tables

	* Added clean_up_stats() function, which erases all saved
	statistics left alone after deleting tables before unlocking
	staistics.

2013-11-07 Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
	* First published version.
