Added part of undo of update row
Extended ma_test1 for recovery testing
Some bug fixes


storage/maria/ha_maria.cc:
  Ignore 'state.split' in case of block records
storage/maria/ma_bitmap.c:
  Added return value for _ma_bitmap_find_place() for how much data we should put on head page
storage/maria/ma_blockrec.c:
  Added undo of deleted row.
  - Added logging of CLR_END records in write_block_record()
  - Split ma_write_init_block_record() to two functions to get better code reuse
  - Added _ma_apply_undo_row_delete()
  - Added ma_get_length()
  
  Added 'empty' prototype for undo_row_update()
  
  Fixed bug when moving data withing a head/tail page.
  Fixed bug when reading a page with bigger LSN but of different type than was expected.
  Store undo_lsn first in CLR_END record
  
  Simplified some code by adding local variables.
  Changed log format for UNDO_ROW_DELETE to store total length of used blobs
storage/maria/ma_blockrec.h:
  Added prototypes for undo code.
storage/maria/ma_pagecache.c:
  Allow plain page to change to LSN page (needed in recovery to apply UNDO)
storage/maria/ma_recovery.c:
  Added undo handling of UNDO_ROW_DELETE and UNDO_ROW_UPDATE
storage/maria/ma_test1.c:
  Extended --test-undo option to allow us to die after insert or after delete.
  Fixed bug in printing key values when using -v
storage/maria/maria_def.h:
  Moved some variables around to be getter alignment
  Added length_buff buffer to be used during undo handling