[ticket/11579] Add basic set of unit tests for validate_data()

This currently includes tests for the string, num, date, match, and
language iso validation functions.

PHPBB3-11579
[ticket/11579] Add remaining unit tests for validate_data functions

This now includes tests for usernames, passwords, emails, and jabber
addresses. A few small changes had to be applied to phpbb_mock_cache
and phpbb_mock_user in order to incorporate needed methods.

PHPBB3-11579
[ticket/11579] Remove unnecessary globals from validate_password()

The globals $db and $user are not used in that function.

PHPBB3-11579
[ticket/11579] Move tests into seperate files depending on needed fixture

PHPBB3-11579
[ticket/11579] Use test case helper class and use assert prefix for method

PHPBB3-11579
[ticket/11579] Move simple tests into seperate files

PHPBB3-11579
[ticket/11579] Rework calls to validate_data_helper

PHPBB3-11579
[ticket/11579] Add missing commas to validate_username_test

PHPBB3-11579
[ticket/11579] Do not extend validate_data_helper

PHPBB3-11579
[ticket/11579] Add method for validating emails for valid MX and mark as slow

A method for setting up the prerequisities also has been added in order to
reduce the amount of necessary code.

PHPBB3-11579
Merge remote-tracking branch 'bantu/ticket/11588' into develop-olympus

* bantu/ticket/11588:
  [ticket/11588] Also use version.phpbb.com in install_update.php.
  [ticket/11583] Use a new lang key instead of giving the old one a new meaning.
  [ticket/11583] Allow FULLTEXT indexes on InnoDB when on MySQL 5.6.4 or higher.
[ticket/11543] Add unit tests for obtain_guest_count()

PHPBB3-11543
[ticket/11543] Add unit tests for obtain_users_online()

PHPBB3-11543
[ticket/11543] Add unit tests for obtain_users_online() with empty forum

PHPBB3-11543
[ticket/11543] Add unit tests for obtain_users_online_string()

PHPBB3-11543
[ticket/11543] Use correct IP addresses and inject time for correct values

PHPBB3-11543
[ticket/11543] Add more users so #hidden <> #normal

PHPBB3-11543
Merge remote-tracking branch 'remotes/nickv/ticket/11543' into develop-olympus

# By Joas Schilling
# Via Joas Schilling
* remotes/nickv/ticket/11543:
  [ticket/11543] Add more users so #hidden <> #normal
  [ticket/11543] Use correct IP addresses and inject time for correct values
  [ticket/11543] Add unit tests for obtain_users_online_string()
  [ticket/11543] Add unit tests for obtain_users_online() with empty forum
  [ticket/11543] Add unit tests for obtain_users_online()
  [ticket/11543] Add unit tests for obtain_guest_count()
[ticket/11601] Split post_setup_synchronisation logic from xml parsing

PHPBB3-11601
[ticket/11601] Add protected method for database sync and call it

PHPBB3-11601