Group radio correctly show length of song.
Some style and spelling fixes.
Fix skiping radio of groups with more than 6000 songs.
Group bookmarks.
Fix some mistakes in VkSettingsPage UI
Add to cache show only on item that not in cache.
Replace cache to VkService
Load songs for groups.
Fix segfault because of trying to play vk song without account.
Fix breaking of current caching.
Group cache options in Vk Settings page.
Bring VkMusicCache to a separate file.
Fix disappearing CopyShareUrl and AddToCache menu items in playlist
menu.
Remove submodules