[vk.com] Added upload_date variable to the test cases that still work.
[vk.com] Updated a test video that has been removed, and added a comment for others to update two other test videos that are also now removed.
[vk.com] Updated the description to include vk.com.
[vk.com] Updated the _VALID_URL regex for the playlist IE. Removed optional m, and named the id group.
[vk.com] Updated the extract_videos_from_page function with a much simpler 1-liner.
[vk.com] Simplified the page_id acquisition by using the id matched in the URL earlier on.
[vk.com] Removed redundant log message -- this information is already being logged.
[vk.com] Added newline at the end of the file.