first pull, merge,test, and get it to work.
The main change is the new replication code - now we have two slave threads
SQL thread and I/O thread. I have also re-written a lot of the code to
prepare for multi-master implementation.
I also documented IO_CACHE quite extensively and to some extend, THD class.
fixed coredump in concat_ws
sql/item_strfunc.h
fixed coredump in concat_ws
sql/mini_client.cc
added mc_mysql_error()
sql/mini_client.h
added mc_mysql_errno()
sql/mysqlbinlog.cc
fixed bug in --postion for local files
sql/slave.cc
more verbose message on bad net reads
sql/sql_repl.cc
send errno on error in mysql_binlog_send
