pgsql: GIN improvements - Replace sorted array of entries in

Log Message:
-----------
GIN improvements
- Replace sorted array of entries in maintenance_work_mem to binary tree,
this should improve create performance.
- More precisely calculate allocated memory, eliminate leaks
with user-defined extractValue()
- Improve wordings in tsearch2

Modified Files:
--------------
pgsql/contrib/tsearch2:
ts_cfg.c (r1.19 -> r1.20)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/tsearch2/ts_cfg.c.diff?r1=1.19&r2=1.20)
pgsql/src/backend/access/gin:
ginbulk.c (r1.1 -> r1.2)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/gin/ginbulk.c.diff?r1=1.1&r2=1.2)
gininsert.c (r1.2 -> r1.3)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/gin/gininsert.c.diff?r1=1.2&r2=1.3)
pgsql/src/include/access:
gin.h (r1.4 -> r1.5)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/gin.h.diff?r1=1.4&r2=1.5)