Added get_current_album_image_url function

[andrymas]

This function gives out an url in a string format to the current's song album cover, it takes an int as a value which reppresents the image array position in the spotify json file. Code snippet with basic usage: String AlbumImageURL = sp.get_current_album_image_url(0); Serial.println(AlbumImageURL);

Output: https://i.scdn.co/image/ab67616d0000b27332f5fec7a879ed6ef28f0dfd

[FinianLandes]

Thanks for that function, i moved it to the right space in the .h as it has to be under simplified and not album functions but in the cpp you had already put it to the right space

[andrymas]

Thank you for merging and fixing it.