Cleanup/optimizations of structures and key usage to make it easier to move key-range-search to handler

Fixed problems with group_concat() and HAVING
Updated crash-me values

into mysql.com:/home/my/mysql-4.1

if doesn't exists or is not writable, then /var/log/mysqld_multi.log, if does not exists
or is not writable, then /tmp/mysqld_multi.log, but only in case the file does not yet
exists in /tmp. Otherwise log will be disabled, unless user explicitely sets it with an
option.

into mysql.com:/home/my/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

for Bug #2385 CREATE TABLE LIKE lacks locking on source and destination table

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

Here is 2nd version.
'reduce/reduce conflicts' issue is fixed

Don't add -debug to server version if MYSQL_SERVER_PREFIX is used
Indentation cleanups

into gluh.mysql.r18.ru:/home/gluh/mysql-4.1.curr

into mysql.com:/home/my/mysql-4.1

the code.

into mysql.com:/home/my/mysql-4.1

into eagle.mysql.r18.ru:/home/vva/work/BUG_2385/mysql-4.1

  'SHOW GRANTS' syntax is added 
  'SHOW GRANTS FOR CURRENT_USER' syntax is added
  'SHOW GRANTS FOR CURRENT_USER()' syntax is added
 CURRENT_USER without parens in expressions(SELECT CURRENT_USER;) 

Fixed bugs in group_concat with ORDER BY and DISTINCT (Bugs #2695, #3381 and #3319)
Fixed crash when doing rollback in slave and the io thread catched up with the sql thread
Set locked_in_memory properly

into ice.snake.net:/Volumes/ice2/MySQL/bk/mysql-4.1

I can't see group_concat_max_len in a list of variables

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

into eagle.mysql.r18.ru:/home/vva/work/BUG_2385/mysql-4.1

into eagle.mysql.r18.ru:/home/vva/work/BUG_2385/mysql-4.1

Bug #2385 "CREATE TABLE LIKE lacks locking on source and destination table" 
(in sql_table.cc and mysql-test/t/synchronization.test)

into eagle.mysql.r18.ru:/home/vva/work/BUG_2397/mysql-4.1

into eagle.mysql.r18.ru:/home/vva/work/BUG_system_db_test/mysql-4.1

for working on aix and so on..

into hegel.local:/home/miguel/bk/mysql-4.1

Final version of patch.

Adds support for specifying of DEFAULT NOW() and/or ON UPDATE NOW()
clauses for TIMESTAMP field definition.
Current implementation allows only one such field per table and
uses several unireg types for storing info about this properties of
field. It should be replaced with better implementation when new
.frm format is introduced.