Add VK Strategy

Added support for vk.com social network.
“My Music” / “Мои Аудиозаписи” page is supported.

Supported features:
- play/pause
- prev/next
- add track to “My Music” (add to favorites action)
- showing track info.
VK added to plist and readme
Merge pull request #51 from S60Dev/master

Add VK Strategy