Fixes for MERGE TABLES and HEAP tables

Docs/manual.texi:
  Updated MERGE table stuff + more
extra/perror.c:
  Added missing error messages
include/myisammrg.h:
  Fixes for MERGE TABLE
include/queues.h:
  Fixes for MERGE TABLE
isam/isamlog.c:
  Fixed hard bug
myisam/mi_log.c:
  cleanup
myisam/mi_open.c:
  Fixed file name format in myisam log
myisam/myisamlog.c:
  Bug fixes
myisammrg/mymrgdef.h:
  Fixes for MERGE TABLE
myisammrg/myrg_create.c:
  Fixes for MERGE TABLE
myisammrg/myrg_open.c:
  Fixes for MERGE TABLE
myisammrg/myrg_queue.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rfirst.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rkey.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rlast.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rnext.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rprev.c:
  Fixes for MERGE TABLE
myisammrg/myrg_rrnd.c:
  Fixes for MERGE TABLE
mysql.proj:
  update
mysys/queues.c:
  Fixed bug when using reverse queues
sql-bench/test-insert.sh:
  Separated some things to get better timings
sql/ha_heap.cc:
  Fixed heap table bug
sql/ha_heap.h:
  Fixed heap table bug
sql/ha_myisam.h:
  Fixed wrong max_keys
sql/ha_myisammrg.cc:
  Fixed MERGE TABLES
sql/ha_myisammrg.h:
  Fixed MERGE TABLES
sql/handler.h:
  Fix for MERGE TABLES and HEAP tables
sql/lex.h:
  Fixed MERGE TABLES
sql/mysql_priv.h:
  Cleanup of code
sql/sql_acl.cc:
  Fixed that privilege tables are flushed at start
sql/sql_lex.h:
  Fixed MERGE TABLES
sql/sql_parse.cc:
  Fixed MERGE TABLES
sql/sql_select.cc:
  Fixes for HEAP tables
sql/sql_table.cc:
  Cleanup
sql/sql_yacc.yy:
  Fixed MERGE TABLES

include/queues.h

@@ -53,6 +53,7 @@ void delete_queue(QUEUE *queue);
 void queue_insert(QUEUE *queue,byte *element);
 byte *queue_remove(QUEUE *queue,uint idx);
 void _downheap(QUEUE *queue,uint idx);
+#define is_queue_inited(queue) ((queue)->root != 0)
 
 #ifdef	__cplusplus
 }