Working:
1. Localize add header to po files.
2. Executables append po entries to po files.
3. Localize delete entryless po files and empty directories
Plus a bunch of clean up.
Change-Id: I58e300eaee4cee948203cc9d3e642ca9462d0d26
Which localize and update help tree files
instead of update_tree.pl.
Use it to update extensions' help.
Next step: use it with general help.
Change-Id: Ife9696bdd8b973ef3cf30626533e38720408179b