Added SQL_SELECT::cleanup() to make it easier to reuse SQL_SELECT item's for sub selects. Needed for proper fix for bug #2479.
Added 'select_to_file' class to be able to merge identical code for select_export and select_dump


client/mysql.cc:
  Print mysql_insert_id() in 'status'
mysys/charset.c:
  after merge fixup
sql/item_func.cc:
  Code cleanup + new comments
sql/opt_range.cc:
  Added SQL_SELECT::cleanup() to make it easier to reuse SQL_SELECT item's for sub selects.
sql/opt_range.h:
  Added SQL_SELECT::cleanup() to make it easier to reuse SQL_SELECT item's for sub selects.
sql/sql_class.cc:
  Added 'select_to_file' class to be able to merge identical code for select_export and select_dump
sql/sql_class.h:
  Added 'select_to_file' class to be able to merge identical code for select_export and select_dump
sql/sql_select.cc:
  Fixed bug when calling 'delete select' in sub selects. (Bug 2479)
  (Test case is already commited to global source repository)