[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
Merge branch 'ticket/11568' into ticket/11568-develop

* ticket/11568:
  [ticket/11568] Add method to get page content
  [ticket/11568] Allow different status codes
  [ticket/11568] Trim the output to allow Tabs before INCLUDE overall_header
  [ticket/11568] Fix common_groups_test.php form handling
  [ticket/11568] Make CookieJar static aswell
  [ticket/11568] Remove manual calls to assert_response_success()
  [ticket/11568] Only use a static version of the client
  [ticket/11568] Any output before the doc type means there was an error
  [ticket/11568] Set client manually so we can increase the cURL timeout
  [ticket/11568] Use Goutte Client to install the board for functional tests

Conflicts:
	tests/test_framework/phpbb_functional_test_case.php
[ticket/develop/11568] Do not directly access $client from tests

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

PHPBB3-11568
[ticket/develop/11568] Remove php extension parameter

We don't support that in 3.1 anymore

PHPBB3-11568
[ticket/develop/11568] Fix some more tests in 3.1

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

PHPBB3-11568
[ticket/11568] Remove unused method

PHPBB3-11568
Merge branch 'ticket/11568' into ticket/11568-develop

* ticket/11568:
  [ticket/11568] Remove unused method
  [ticket/11568] Only assert string when doctype is there at all
[ticket/develop/11568] Remove unneccessary second call with wrong arguments

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

PHPBB3-11568