Add commands to add and list menus and menu items.
Changes since 7.x-3.4:
* Document menu commands in README
* Remove meta:menu:title definition from menu.drush.inc, so that menu commands are grouped with drush extras.
* Fix error in ambiguous key message; also, if ambiguous arg is the name of a module, always assume --module=arg in favor of the other alternative.
* Add menu management drush commands
Support Drupal 7 in block commands. Also, provide a shortcut for block commands where arguments can be used in place of options in cases where doing so is unambiguous.
The drush_extras project has now been restored, with new commads. The old commands in drush_extras have been removed, as they have moved to drush core.