For consistency mark some dates and strings for localization (Was: Improve consistency of that which dates are marked for localization)

Hello,

I'm attaching a new patch. I hope that it won't be forgotten.

[[[
Mark some dates and strings for localization.

* subversion/libsvn_diff/diff_file.c
  (output_unified_default_hdr): Mark a date for localization.
* subversion/svn/list-cmd.c
  (print_dirent): Mark dates for localization.
* subversion/svnlook/main.c
  (generate_label): Mark strings for localization.
  "txn" and "rev" are translatable here.

Patch by: Arfrever Frehtes Taifersar Arahesis <arfrever.fta@gmail.com>
]]]

-- 
Arfrever Frehtes Taifersar Arahesis