[ticket/11568] Use Goutte Client to install the board for functional tests

PHPBB3-11568
[ticket/11568] Set client manually so we can increase the cURL timeout

PHPBB3-11568
[ticket/11568] Any output before the doc type means there was an error

Change is needed to allow "Warning:" in the HTML body

PHPBB3-11568
[ticket/11568] Only use a static version of the client

PHPBB3-11568
[ticket/11568] Remove manual calls to assert_response_success()

PHPBB3-11568
[ticket/11568] Make CookieJar static aswell

PHPBB3-11568
[ticket/11568] Fix common_groups_test.php form handling

PHPBB3-11568
[ticket/11568] Trim the output to allow Tabs before INCLUDE overall_header

PHPBB3-11568
[ticket/11568] Allow different status codes

PHPBB3-11568
[ticket/11568] Add method to get page content

PHPBB3-11568
[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/11568] Only assert string when doctype is there at all

PHPBB3-11568
[ticket/11568] Remove unused method

PHPBB3-11568
[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/11568] Use static calls for static methods

PHPBB3-11568
[ticket/11568] Invert logic for asserting the response

PHPBB3-11568
[ticket/11568] Add comma at end of array key-value couple

PHPBB3-11568
[ticket/11568] Split status code and html debug assertion into two methods

PHPBB3-11568