add video download from VK.com Social Network

It would be really nice to add support to video download from VK.com Social Network (V Kontakte) - they have groups which offer wide archives of soccer games and many other stuff not available from youtube or other sites.

Example of such video - https://vk.com/full_football_matches?z=video-12919375_456253568%2F233fa935a78b0ce8d5%2Fpl_wall_-12919375

Thank you!