Some simple optimzations, more comments and indentation changes.
Add ` around database in 'use database' in binary log.
Moved max_error_count and max_warning_count to variables struct.
Removed SHOW_WARNS_COUNT and SHOW_ERRORS_COUNT calls.
Changed string functions to use character set of first string argument as default return characterset
(Each string function can change the above assumption if needed)
(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
