Get some more information from a video

[memento]

Hi, I needed to be able to get some more informations from a video.

Example :

• view_count
• like_count
• dislike_count
• repost_count
• average_rating

I added the fields in the mapping class, also some getters and I updated a test class accordingly. I also updated you README.md with the Maven way of importing your project.

Maybe you'll find that interresting enough to merge.

Regards and thanks for your work.

[memento]

I forgot to update version in pull request. Now, done.