Additional grammar rules for ru (Russian)

Kaganer, can you give a look to the concern raised on the patch?

I'm sorry for long time of reply, this was my vacation;) See tests of currently state of this feature in various projects (for Russian language):

• in Russian Wikipedia
• in Russian Wikinews
• in Russian Wikisource
• in Russian Wikiquote
• in Russian Wiktionary
• in Russian Wikiversity
• in Russian Wikivoyage
• in Russian Wikibooks
• in Wikidata
• in Commons

Currentlly worked only genitive case (partially). Russian localized names of grammatical cases is not worked. This bad workspace for translators.