order directly from the index instead of using a filesort.


mysql-test/mysql-test-run.sh:
  [ -n $SKIP_TEST ] --> [ -n "$SKIP_TEST" ]; portability fix
mysql-test/r/order_by.result:
  Added test for ORDER BY DESC optimization
mysql-test/t/order_by.test:
  Added test for ORDER BY DESC optimization
sql/opt_range.cc:
  Added QUICK_SELECT_DESC class which implements ORDER BY DESC optimization.
sql/opt_range.h:
  Added QUICK_SELECT_DESC class which implements ORDER BY DESC optimization.
sql/sql_select.cc:
  Added QUICK_SELECT_DESC class which implements ORDER BY DESC optimization.
BitKeeper/etc/ignore:
  Added .gdbinit .vimrc to the ignore list
BitKeeper/etc/logging_ok:
  Logging to logging@openlogging.org accepted