Implement the system tablespace tagging described on the wiki:
https://svn.innodb.com/innobase/InnoDB_version_and_feature_compatibility

A brief description of the changes:

* The file format tag will be saved in the trx system page, starting at
  (UNIV_PAGE_SIZE - 16) for 8 bytes.
* The configuration parameter innodb_file_format_check is introduced.
  This variable can be set to on/off and any of the supported file
  formats in the configuration file, but can only be set to any of
  the supported file formats during runtime. The default is on.
* During table create/open, check the current file format against
  the max in file_format_max. If the current file format is newer,
  update file_format_max and tag the system tablespace with the
  newer one in a normal mtr.
* During startup, write the tag to the error log and check it against
  DICT_TF_FORMAT_MAX. Refuse to start with error, if
  -- DICT_TF_FORMAT_MAX < the tag, and
  -- innodb_file_format_check is ON
  Print out a warning , if
  -- DICT_TF_FORMAT_MAX < the tag, but
  -- innodb_file_format_check is off
* The system tablespace tag is re-settable using:
  set innodb_file_format_check = <file_format>

Approved by:	Sunny