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
(All commit emails since 4.0.1 checked)
This had to be done now, before the 4.1 tree changes to much, to make it easy to propagate bug fixes to the 4.1 tree.
Fixes for embedded server
Made key_cache more configurable
Fixed that one can change key blocksize in MyISAM
A lot of optimizations to make MyISAM slightly faster
