Added --verbose-sql option to indexer
Renaming LyricsCache

Because that's what it is, a cache.
Not caching lyrics anymore

I am not sure if it's allowed to cache lyrics, instead I'll redirect the
traffic to the lyric's website. Just to be sure.
Documenting scrapers' new behaviour
Fixed AttributeError

AttributeError: 'Headers' object has no attribute 'update'
Forced Flask-Restful to run custom options method
Headers are always set in after_request
Improved range-related code

Created a function that obtains the range from the header and extracted the
regex to compile it only once.
The Accept-Ranges headers is added always

Not only when partial content is requested
Improved CORS docs
Normalizing resources' names
Fix for OPTIONS method to an instance

OPTIONS /track/1
TypeError: options() got an unexpected keyword argument 'track_id'