Some limit optimization


BitKeeper/deleted/.del-ib_config.h.in~9e57db8504e55b7:
  Delete: innobase/ib_config.h.in
BitKeeper/deleted/.del-ib_config.h~7539e26ffc614439:
  Delete: innobase/ib_config.h
client/errmsg.c:
  Moved error messages from libmysqld/
client/mysql.cc:
  Removed warnings
include/errmsg.h:
  New info for embedded versions
include/mysql_com.h:
  Fixes for embedded MySQL
libmysql/errmsg.c:
  Fixes for embedded MySQL
libmysqld/Makefile.am:
  Added HANDLER code
libmysqld/lib_sql.cc:
  Fixes for embedded MySQL
libmysqld/lib_vio.c:
  Fixes for embedded MySQL
BitKeeper/etc/ignore:
  Added libmysqld/sql_handler.cc to the ignore list
libmysqld/libmysqld.c:
  Fixes for embedded MySQL
mysql-test/r/null_key.result:
  Fixed result for 4.0
sql/net_serv.cc:
  Fixes for embedded MySQL
sql/sql_parse.cc:
  Fixes for embedded MySQL where the query could be a const char*
sql/sql_select.cc:
  Added limit optimization
sql/sql_select.h:
  Added limit optimization