actually we do need binding_of_caller explicitly in the Gemfile
use lyriki gem

[#65]
replace #fetch_data_for_artist with Lyriki

[#65]
replace #fetch_lyrics

[#65]
LyricsWiki module has been replaced by Lyriki::Legacy

[#65]
Merge pull request #72 from alxndr/gemify

use external lyriki gem instead of internal LyricsWiki module