Youtube plugin improvements

[NicolasGuilloux]

Fixes

Fix the youtube persistent information. Disable the preview button when the player is outside a playlist.
Fix #218 Add the ads control. It will mute during the ad and skip it automatically.

[NicolasGuilloux]

I don't understand why the check failed. It works on my computer very well :(

[ColinDuquesnoy]

Thank you for your contribution!

I don't understand why the check failed. It works on my computer very well :(

Don't worry about it, this was just an intermittent infrastructure issue (chocolatey failed to download qbs). I've rebuild your PR and the check now passes on AppVeyor...

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About the PR, may I ask you to split the PR in two and close this one? (one for the youtube plugin fix and another for kodi)
It seems like the PR fixes #218, so, please add a comment with "fix #218" in the new youtube PR so that the corresponding issue will get closed automatically when I'll merge the PR (see Closing Issues via Pull Requests )

About the kodi plugin, I have a few minor nitpicks:

1. use lowercase for the plugin directory
2. Use white instead of blue in the kodi logo (so that the logo looks consistent with other logos)

[NicolasGuilloux]

Okay I really struggle to use Git. I mean, I learned barely how to use it but it is the first time I use advanced features, so sorry for the many mistakes. I try to figure this out without messing up everything ;)

[NicolasGuilloux]

Okay I made things clear, wonderful! I definitely need to practice ;) This pull request looks ready to go!

For the Kodi stuff, as I found a bug, I will first solve it and then create a new pull request to avoid spamming your git.

[ColinDuquesnoy]

Okay I made things clear, wonderful! I definitely need to practice ;) This pull request looks ready to go!

Thank you! 👏

For the Kodi stuff, as I found a bug, I will first solve it and then create a new pull request to avoid spamming your git.

Fine 👍