after Monty's review.
- Item_param was rewritten.
- it turns out that we can't convert string data to character set of
connection on the fly, because they first should be written to the binary
log.
To support efficient conversion we need to rewrite prepared statements
binlogging code first.
Made a some new buffers thread specific and changeable.
Resize of key_buffer.
AUTO_COMMIT -> AUTOCOMMIT
Fixed mutex bug in DROP DATABASE
Fixed bug when using auto_increment as second part of a key where first part could include NULL.
Split handler->extra() to extra() and extra_opt() to be able to support thread specific buffers.
Don't write message to error log when slave reconnects becasue of timeout.
Fixed possible update problem when using DELETE/UPDATE on small tables
(In some cases we used index even if table scanning would be better)
A lot of minior code cleanups
