Make Panels 1 compatible with i18n (patch)

From Agaric's soon-to-be-obsolete-contributions department, here's a patch that makes panels used for showing nodes (as opposed to blocks, views, and custom) play well with Internationalization package's translation module. It applies to content_types/node.inc (run patch < panels_i18n_translated_node_compatibility.patch from in the panels/ directory).

It picks the language currently in use if available, and the default language if not. (Note to self: see what happens if default language doesn't for a node.)

Detail and background here:
http://agaricdesign.com/note/remixing-drupal-agaric-way-multilingual-panels

We don't expect this to get into Drupal 5.x-1 branch even if there is another release, but if you absolutely must make a multilingual site before the i18n-ized Drupal 6 and the further wizardized Panels 2 are both ready, this might help.

^{benjamin, Agaric Design Collective}