l10n_update 7.x-2.0-rc1

This is a backport of the Drupal 8 (core) Interface translation update function.

Changes for site builders and admins

• Improved performance for translation update. Especially for lange translation files (e.g. Drupal core and Views), both with manual update and with cron updates.
• Impoved usability of the translation status page at admin/config/regional/translate/update
• Remote-only translation source is no longer supported. 'Local only' and 'Remote and local' are still supported.
• Cron update intervals have changed to Weekly and Monthly. Daily updates are no longer supported. However the weekly updates now checks and updates all expired translations, where previously only a limited number of projects where checked and updated on each cron interval.

Changes for developers

• The translations directory is now required.
• New .info parameter 'interface translation project'. This can be used to determine the project where a modules' translations belong to. This can be usefull for custom modules to use a common translation file. All modules sharing the same translation will have their 'interface translation project' set to the same value.
• No longer supports .info parameters 'l10n server' and 'l10n url'. 'l10n path' is still supported. Custom translation sources must now use a combination of:
• Use variable 'l10n_update_default_update_url' to change the translation source globally. Defaults to 'http://ftp.drupal.org/files/translations/%core/%project/%project-%versio...'
• Use hook_l10n_update_projects_alter() to change the translation source on a project by project basis by changing or setting 'l10n path' and/or 'interface translation project' values.
• API change: No longer supports hook_l10n_servers(). See above for alternatives.
• API change: The $project data in hook_l10n_update_projects_alter() will no longer contain 'l10n server' and 'l10n url' parameters. $project parameter 'interface translation project' is new, 'l10n path' is still supported.
• New variable 'l10n_update_import_enabled' can be used to disable the import of translations when enabling modules and adding languages.
• Test scripts added.