- new program maria_read_log to display and apply log records
found in a Maria log (see file's revision comment)
- minor, misc fixes


storage/maria/Makefile.am:
  new program maria_read_log
storage/maria/ha_maria.cc:
  create control file if missing
storage/maria/ma_blockrec.c:
  0 -> LSN_IMPOSSIBLE; comments
storage/maria/ma_checkpoint.h:
  preparations for Checkpoint module
storage/maria/ma_close.c:
  comment
storage/maria/ma_control_file.c:
  renaming constants.
  Possibility to say "open control file but don't create it if it's
  missing" (used by maria_read_log which does not want to create
  anything)
storage/maria/ma_control_file.h:
  renaming constants
storage/maria/ma_create.c:
  I had duplicated "linkname" and "linkname_ptr", now I see it's not
  needed, reverting. Indeed those variables don't contain interesting
  information; fixing log record accordingly (the links are in
  ci->data/index_file_name). Storing keystart in log record is needed,
  to know at which size we must extend the file if we replay
  LOGREC_CREATE_TABLE.
storage/maria/ma_loghandler.c:
  some structures need to be known to maria_read_log.c, taking
  them to ma_loghandler.h
storage/maria/ma_loghandler.h:
  we have page_store, adding page_korr.
  translog_lock() made public, because Checkpoint will need it (to
  write to control file).
  Some structures moved from ma_loghandler.c because maria_read_log.c
  needs them (needs to know the execute-in-REDO-phase hooks of each
  record).
storage/maria/ma_loghandler_lsn.h:
  constants defined in ma_control_file.h serve everywhere,
  and they relate to LSNs, so putting them in ma_loghandler_lsn.h.
  Stronger constraints in LSN_VALID().
storage/maria/ma_pagecache.c:
  renaming constants
storage/maria/ma_recovery.h:
  copyright
storage/maria/ma_test1.c:
  new prototype
storage/maria/ma_test2.c:
  new prototype
storage/maria/trnman_public.h:
  double-inclusion safe
storage/maria/unittest/ma_control_file-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_multigroup-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_multithread-t.c:
  constants renamed, new prototype
storage/maria/unittest/ma_test_loghandler_pagecache-t.c:
  constants renamed, new prototype
storage/myisam/mi_close.c:
  comment
storage/maria/maria_read_log.c:
  program to read and print log records from a Maria transaction log,
  and optionally apply them to tables. Very basic, early version.
  Should serve as a base for Recovery's code. Designed to be idempotent.
  Create a log by running maria.test, then cd to var/master-data
  and run "maria_read_log --only-display" to see info about records;
  run "maria_read_log --display-and-apply" to also apply the records
  to tables (it's more interesting if you first wipe out the
  tables in var/master-data/test, to see how they get re-created).
  Only a few records are handled by now: LONG_TRANSACTION_ID,
  COMMIT, FILE_ID, REDO_CREATE_TABLE; place is ready for
  REDO_INSERT_ROW_HEAD where I could use Monty's help (search for
  "Monty" in the file). Note: changes to the index pages, index's header
  and bitmap pages are not properly logged yet, so don't expect
  the program to work with that.