[ticket/11259] Make phpbb_admin_path available everywhere

PHPBB3-11259
[ticket/11259] Also make adm_relative_path available in the container

PHPBB3-11259
[ticket/11259] adm_relative_path -> phpbb_adm_relative_path

We can assume they properly format their config settings, right?

PHPBB3-11259
[ticket/11259] htmlspecialchars($phpbb_admin_path)

PHPBB3-11259
[ticket/11291] phing: Make sure composer is available before calling it.

Older versions of the tree didn't use it.

PHPBB3-11291
[ticket/11293] Add a note that mysqli should be in front of mysql.

php 5.5 alpha 2 deprecated mysql extension, prefer mysqli if
both are available.

PHPBB3-11293
[ticket/11291] phing: Correct dependencies of composer target.

This command runs composer in the phpBB tree and does not write to the build
folders. Thus, it does not have to depend on prepare and clean targets.

PHPBB3-11291
[ticket/11291] phing: Add --dev to composer install.

The composer target runs composer in the phpBB tree in order to load
dependencies for testing. The testing framework may have additional
development dependencies (e.g. goutte). We also have to load those.

PHPBB3-11291
[ticket/11291] phing: Add description for composer target.

PHPBB3-11291
[ticket/11291] phing: Adjust directory format of composer exec.

Adjust the directory format to what all the other exec calls are using.

PHPBB3-11291
[ticket/11291] phing: The package target does not depend on composer.

The packaging process does not require running composer in the phpBB tree.
It does however require running composer on the git exports, but this is not
what the composer target does.

PHPBB3-11291
[ticket/11291] phing: Remove no longer needed create-package target.

PHPBB3-11291
[ticket/11291] phing packaging: Export composer.phar and install dependencies.

PHPBB3-11291
[ticket/11291] phing: Exclude vendor folder from diffs.

Otherwise we end up with very huge diffs and the build process is severely
slowed down.

PHPBB3-11291
[ticket/11291] phing: Add checkreturn="true" to all new commands.

PHPBB3-11291
[ticket/11291] phing: Also add checkreturn="true" to composer execution.

PHPBB3-11291
Merge PR #1162 branch 'bantu/ticket/11291' into develop-olympus

# By Andreas Fischer
# Via Andreas Fischer
* bantu/ticket/11291:
  [ticket/11291] phing: Also add checkreturn="true" to composer execution.
  [ticket/11291] phing: Add checkreturn="true" to all new commands.
  [ticket/11291] phing: Exclude vendor folder from diffs.
  [ticket/11291] phing packaging: Export composer.phar and install dependencies.
  [ticket/11291] phing: Remove no longer needed create-package target.
  [ticket/11291] phing: The package target does not depend on composer.
  [ticket/11291] phing: Adjust directory format of composer exec.
  [ticket/11291] phing: Add description for composer target.
  [ticket/11291] phing: Add --dev to composer install.
  [ticket/11291] phing: Correct dependencies of composer target.
  [ticket/11291] phing: Make sure composer is available before calling it.
Merge PR #1162 branch 'develop-olympus' into develop

# By Andreas Fischer
# Via Andreas Fischer (1) and Oleg Pudeyev (1)
* develop-olympus:
  [ticket/11291] phing: Also add checkreturn="true" to composer execution.
  [ticket/11291] phing: Add checkreturn="true" to all new commands.
  [ticket/11291] phing: Exclude vendor folder from diffs.
  [ticket/11291] phing packaging: Export composer.phar and install dependencies.
  [ticket/11291] phing: Remove no longer needed create-package target.
  [ticket/11291] phing: The package target does not depend on composer.
  [ticket/11291] phing: Adjust directory format of composer exec.
  [ticket/11291] phing: Add description for composer target.
  [ticket/11291] phing: Add --dev to composer install.
  [ticket/11291] phing: Correct dependencies of composer target.
  [ticket/11291] phing: Make sure composer is available before calling it.
Merge PR #1130 branch 'EXreaction/ticket/11259' into develop

* EXreaction/ticket/11259:
  [ticket/11259] htmlspecialchars($phpbb_admin_path)
  [ticket/11259] adm_relative_path -> phpbb_adm_relative_path
  [ticket/11259] Also make adm_relative_path available in the container
  [ticket/11259] Make phpbb_admin_path available everywhere

Conflicts:
	phpBB/install/index.php
	phpBB/install/install_update.php
Merge remote-tracking branch 'p/ticket/11293' into develop-olympus

* p/ticket/11293:
  [ticket/11293] Add a note that mysqli should be in front of mysql.