renamed extras/po to an intelligible name

INSTALL.md

@@ -165,13 +165,13 @@ Please note that it doesn't makes much sense to use KDF keys and
 steganography, since the latter will invalidate the brute-forcing
 protection. For details on the issue see [KNOWN_BUGS.md](KNOWN_BUGS).
 
-### extras/po (translations)
+### extras/translations/
 
 There are translations available for Tomb and they are installed by
 default. If you wish to update them manually navigate to extras/po
 and run 'make install' as root:
 
-    cd extras/po
+    cd extras/translations
     sudo make install
 
 # Tomb support in other applications

Makefile

@@ -17,7 +17,7 @@ install:
 	install -Dm644 doc/${PROG}.1 ${DESTDIR}${MANDIR}/man1/${PROG}.1
 	@echo
 	@echo "Tomb is installed succesfully. To install language translations, make sure"
-	@echo "gettext is also installed, then 'cd extras/po' and 'make install' there."
+	@echo "gettext is also installed, then 'cd extras/translations' and 'make install' there."
 	@echo
 	@echo "Look around the extras/ directory, it contains other interesting modules."
 	@echo