Adding images using pytube thumbnails

[mraza007]

Displaying Images of the video with a link

[mraza007]

We can use pytube module to extract thumbnails and display with links

[jslay88]

PR #14 Addressed this for the GUI. Also renamed the download_youtube_video file to utils, and built a function for getting the URL's with different qualities.

Only thing left to do for this issue, is implement it within the CLI.

[mraza007]

I see