update genius_album to handle "features" to the info argument

[JosiahParry]

PR #20 enabled the value "features" to the genius_url() function. This precipitates through to genius_album(). There is now a duplicated column track_title.

See below for an example:

DAMN <- genius_album(artist = "Kendrick Lamar", album = "DAMN.", info = "features")

[JosiahParry]

@natebarr64 if you want to try and take a stab at this go ahead.

[natebarr64]

Thanks for the pull! I did a quick fix by removing track titles in the "features" switch of genius_url.

Bumped into another error with parsing some albums. This input:

Doris <- genius_album(artist = "Earl Sweatshirt", album = "Doris", info = "features")

leads to:

Error in mutate_impl(.data, dots) : 
  Evaluation error: Evaluation error: object 'lyric' not found.. 

Ill try to figure this out when I get a chance.

[JosiahParry]

This error is caused by a song with no lyrics. https://genius.com/Earl-sweatshirt-523-lyrics

The only text is "[Produced by RandomBlackDude]". The spread is causing the error.

[JosiahParry]

Looks like a potential work around is to bind a row to the data frame if its empty for good measure then filter out that row

[JosiahParry]

Fixed in #24