[ticket/11303] add S_TZ_PRESELECT template var

add a new template variable to check if timezone has already been selected
by the user while registeration.

PHPBB3-11303
[ticket/11303] use S_TZ_PRESELECT in subsilver

PHPBB3-11303
[ticket/11303] remove additional brackets

PHPBB3-11303
[ticket/11303] rename attribute to timezone-preselect

PHPBB3-11303
[ticket/11323] Correctly treat variables in template defines

Previously, any template variables that were used when defining a variable
were treated as strings. This is a regression to phpBB 3.0. With this
patch the template variables will be properly parsed.

PHPBB3-11323
[ticket/11323] Enable tests for inclusion of defined variables

PHPBB3-11323
[ticket/11323] Reduce additional code and revert regex to previous one

PHPBB3-11323
[ticket/11383] Correctly revert modules added/removed by migrator

PHPBB3-11383
[ticket/11404] Return empty array of avatar data if $row is empty

While creating a group in the acp, the group data ($group_row) is empty.
Due to that array_combine in phpbb_avatar_manager::clean_row() will cause
PHP Warnings. In addition to that the required indexes 'avatar',
'avatar_width', 'avatar_height', and 'avatar_type' won't be defined. This
patch will solve that issue.

PHPBB3-11404
[ticket/11404] Use a default data row if $row is empty in clean_row()

A statically defined $default_row will be used inside the
phpbb_avatar_manager::clean_row() method if the $row passed to it is
empty.

PHPBB3-11404
Merge remote-tracking branch 'remotes/Blitze/ticket/11383' into develop

# By OpenShift guest
# Via OpenShift guest
* remotes/Blitze/ticket/11383:
  [ticket/11383] Correctly revert modules added/removed by migrator
Merge remote-tracking branch 'remotes/marc/ticket/11323' into develop

# By Marc Alexander
# Via Marc Alexander
* remotes/marc/ticket/11323:
  [ticket/11323] Reduce additional code and revert regex to previous one
  [ticket/11323] Enable tests for inclusion of defined variables
  [ticket/11323] Correctly treat variables in template defines
Merge remote-tracking branch 'remotes/dhruv/ticket/11303' into develop

# By Dhruv
# Via Dhruv
* remotes/dhruv/ticket/11303:
  [ticket/11303] rename attribute to timezone-preselect
  [ticket/11303] remove additional brackets
  [ticket/11303] use S_TZ_PRESELECT in subsilver
  [ticket/11303] add S_TZ_PRESELECT template var
[ticket/11404] Convert manager_test to UNIX line endings

PHPBB3-11404
[ticket/11404] Add tests for phpbb_avatar_manager::clean_row()

PHPBB3-11404
[ticket/11404] Remove version ID from manager_test.php file header

PHPBB3-11404
[ticket/11433] Rename CSS class "jalert" to "phpbb_alert"

This missing change caused the loading info to appear during ajax
requests. With this patch it will be properly hidden as it should.

PHPBB3-11433
[ticket/11310] Add hashes to action links to prevent CSRF attacks

PHPBB3-11310
Merge remote-tracking branch 'remotes/nickv/ticket/11310' into develop

# By Joas Schilling
# Via Joas Schilling
* remotes/nickv/ticket/11310:
  [ticket/11310] Add hashes to action links to prevent CSRF attacks
Merge remote-tracking branch 'remotes/Marc/ticket/11433' into develop

# By Marc Alexander
# Via Marc Alexander
* remotes/Marc/ticket/11433:
  [ticket/11433] Rename CSS class "jalert" to "phpbb_alert"