Fixed bug in DISTINCT


Docs/manual.texi:
  Updated Changelog
  Cleaned up adding character sets
merge/open.c:
  skip comments
myisam/mi_check.c:
  Fixed bug when sorting index on Windows
myisammrg/myrg_info.c:
  Use only portable printf arguments
myisammrg/myrg_rrnd.c:
  Use only portable printf arguments
mysql-test/r/distinct.result:
  Added test case for bug in distinct
mysql-test/r/merge.result:
  Added test for ALTER TABLE
mysql-test/t/distinct.test:
  Added test case for bug in distinct
mysql-test/t/merge.test:
  Added test for ALTER TABLE
sql-bench/crash-me.sh:
  Fixed portability issues
sql/ha_myisammrg.cc:
  Fixed for ALTER TABLE on MERGE tables
sql/item_sum.cc:
  Fixed bug in DISTINCT
sql/sql_db.cc:
  Added test of namelen in check_db_name
sql/sql_select.cc:
  Fixed bug in DISTINCT
sql/sql_select.h:
  Fixed bug in DISTINCT
sql/sql_table.cc:
  Fixed ALTER TABLE on MERGE tables
sql/table.cc:
  Added test of namelen in check_db_name
sql/table.h:
  Fixed ALTER TABLE on MERGE tables