Correct how to activate .git/hooks/pre-commit.sample

* README-hacking (Making commits locally): Update the command that activates
pre-commit.sample because it is now being distributed differently.

Copyright-paperwork-exempt: Yes
Updated some translations from the Translation Project.

Updated the Estonian, Spanish, Finnish, Dutch, Polish, Brazilian
Portuguese, Russian, Serbian, Swedish, French, Vietnamese, Czech,
Ukranian and German translations.