Import translatins from .po files to .glom examples
Export .po for .glom examples: Try to split lines appropriately.

* glom/libglom/translations_po.cc: get_po_context_for_item():
  Try to mimick how the translation tools split the lines,
  apparently at roughly 80 characters, but after the space before
  that.
* examples/po_files/*/*.po: Export from the .glom .files.