Update Macedonian (mk) plural form

I've just noticed that in Launchpad Macedonian has got only 2 plural forms, whereas in some GNOME and KDE applications it's got 3. This would need to be checked and the plural forms updated accordingly.

* Launchpad has:
nplurals=2;
(n % 10 == 1 && n % 100 != 11) ? 0 : 1

* Nautilus, Evolution (GNOME) have:
"Plural-Forms: nplurals=3; plural= n==1 || n%10==1 ? 0 : 1\n"
(Confusingly enough, http://l10n.gnome.org/teams/mk says nplurals=2; plural= n==1 || n%10==1 ? 0 : 1)

* Dolphin (KDE) has:
"Plural-Forms: Plural-Forms: nplurals=3; plural=n%10==1 ? 0 : n%10==2 ? 1 : "
"2;\n"

The Macedonian translators should be able to confirm which is the correct form.