Fixed clear issues of bitvector and memory allocation issues


sql/bitvector.cc:
  Made bitvector memroot class
sql/bitvector.h:
  Made bitvector memroot class
sql/handler.cc:
  Need to add updated fields to read set to ensure that they are
  updated since the update code doesn't update if records haven't
  changed
  Added DBUG printout's
sql/handler.h:
  Moved clear of bitvector's to reset function
  Introduced ha_reset for this purpose to ensure that it isn't
  necessary to perform this clear in all handlers.
sql/lock.cc:
  Removed clear that has been moved to ha_reset
sql/opt_range.cc:
  Changed reset to ha_reset
  Added delete file
sql/sql_base.cc:
  Removed clear and changed reset to ha_reset
sql/sql_insert.cc:
  Removed clear and changed reset to ha_reset
sql/sql_select.cc:
  Made sure delete file is done if needed
sql/sql_table.cc:
  Added delete file in another place needed
sql/sql_update.cc:
  Bug for multi-update fixed