Fixed bug #320.
Some new tests and cosmetic changes.
Another strcasecmp() replaced.


mysql-test/r/sp.result:
  Moved SP tests from subselect and added some more.
mysql-test/r/subselect.result:
  Moved SP tests to sp.test.
mysql-test/t/sp.test:
  Moved SP tests from subselect and added some more.
mysql-test/t/subselect.test:
  Moved SP tests to sp.test.
sql/sp.cc:
  Don't close derived tables.
sql/sp_head.cc:
  Minor layout and comment fix.
sql/sp_head.h:
  Minor comment fix.
sql/sql_derived.cc:
  Don't set org_table_list->derived to 1 when debugging, as this breaks certain
  subselect args to SPs.
sql/sql_parse.cc:
  Post-fix of bugfix (free memory on error), and added comment.
sql/sql_yacc.yy:
  Another strcasecmp() replaced.