requested by Monty for Bug#1647 (No way to determine what size 
blob/clob is being returned into bound buffer)


include/mysql.h:
  Implementation of mysql_stmt_attr_get and mysql_stmt_attr_set 
  requested by Monty for Bug#1647.
libmysql/libmysql.c:
  Implementation of mysql_stmt_attr_get and mysql_stmt_attr_set 
  requested by Monty for Bug#1647.
libmysql/libmysql.def:
  Windows .defs added for new API calls