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)