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)
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
Allow delete of crashed MyISAM tables
Fixed bug when BLOB was first part of key
Fixed bug when using result from CASE in GROUP BY
Fixed core-dump bug in monthname()
Optimized calling of check_db_name()