Call pthread_mutex_destroy() on not used mutex.
Changed comments in .h and .c files from // -> /* */
Added detection of mutex on which one didn't call pthread_mutex_destroy()
Fixed bug in create_tmp_field() which causes a memory overrun in queries that uses "ORDER BY constant_expression"
Added optimisation for ORDER BY NULL
Remember UNION for ALTER TABLE
Added test for if we are supporting transactions.
Don't allow REPLACE to replace a row when we have generated an auto_increment key
Fixed bug when using BLOB keys
Fixed bug in SET @variable=user.
