Added check for youtube destroy method in beforeDestroy

[basschuitema]

We're using Vue-storybook (instead of Vue-Play) together with vue-youtube-embed. When I change a property of a component (in storybook) the beforeDestroy is executed, but for some reason the Youtube API destory method is not a function.

The error:
Error in beforeDestroy hook: "TypeError: this.player.destroy is not a function"

To prevent this I added a check if the method is there, before executing it. This solves the issue.

[kaorun343]

@basschuitema

Hi. Thanks for your PR.

Could you update the file in source instead of lib/vue-youtube-embed.js?
Then, I'll merge this.

[basschuitema]

Thanks for your reply!
I reverted the commit on the /lib/ directory and applied the fix to the source directory.
Greets

[basschuitema]

@kaorun343
Thanks for merging my pull request. Can you tell me when you are going to release the next version with this fix?

[kaorun343]

@basschuitema

I've done doing this. version 2.1.2 is available now.