This includes both code and test cases.

Solution according to the comments made by Guilhem
- rpl_relayrotate  Remove the SHOW SLAVE STATUS  It is not needed.
- rpl_until, rpl_deadlock Omit the printing of the "Slave_IO_Running" value

 - Fixed problem, only detect comment if the # is on start of line AND starting line of the current command.
 - Wrote tests for most of the mysqltest commands, added stricter checking of correct syntax.

end of the test, causing subsequent tests to fail.

This saves one byte per Query_log_event on disk compared to 5.0.[0..3]. Compatibility problems with 5.0.x where x<4
are explained in the comments in log_event.cc. Putting back s/my_open(O_TRUNC)/(my_delete+my_create) change which had
been wiped away by somebody doing a wrong 4.1->5.0 merge (which happened just
before 5.0.3 :( ). Applying it to new events for LOAD DATA INFILE.
If slave fails in Execute_load_query_log_event::exec_event(),
don't delete the file (so that it's re-usable at next START SLAVE).
And (youpi!) fix for BUG#3247 "a partially completed LOAD DATA INFILE is not
executed at all on the slave" (storing an Execute_load_query_log_event
to binlog, with its error code, instead of Delete_file_log_event).

"After Monty's review" changes to the fix for BUG#8325 "Deadlock in replication thread stops replication":
s/sleep/safe_sleep (thread safe); sleep 0/1/2/3/4/5/5/5 (get slave less late);
no message on error log (deadlock is too common sometimes), a global counter
instead (SHOW STATUS LIKE 'slave_retried_transactions').
Plus a fix for libmysql/Makefile.shared

Now one can use user variables as target for data loaded from file
(besides table's columns). Also LOAD DATA got new SET-clause in which
one can specify values for table columns as expressions.

For example the following is possible:
LOAD DATA INFILE 'words.dat' INTO TABLE t1 (a, @b) SET c = @b + 1;

This patch also implements new way of replicating LOAD DATA.
Now we do it similarly to other queries.
We store LOAD DATA query in new Execute_load_query event
(which is last in the sequence of events representing LOAD DATA).
When we are executing this event we simply rewrite part of query which
holds name of file (we use name of temporary file) and then execute it
as usual query. In the beggining of this sequence we use Begin_load_query
event which is almost identical to Append_file event

Last part of fix for BUG#7998 "Replication should be more clever about when to replicate RELEASE_LOCK()" + fixes after merge

in slave SQL thread: if a transaction fails because of InnoDB deadlock or innodb_lock_wait_timeout exceeded,
optionally retry the transaction a certain number of times (new variable --slave_transaction_retries).