#43 Spotify integration

Read playlists from Spotify and automatically search the tracks online and attempt to download them.

A developer account is needed from https://developer.spotify.com/

When the user calls the spotify command for the first time a guide is displayed on how the user can retrieve the needed keys.

The following settings are needed:

The label ID3 tag is still empty. This needs to be fixed before merging

This is actually an addition for issue #44.

When automatically searching for a remix of a song, the base version of the song is also found sufficient enough to download instead of the requested remix version.

This should be looked at. If the song is not a specific remix it should be added to the FAIL list and possibly flagged to try to find it manually. By adding a not sure flag to the item.

The playlist tag is still empty. It is described in the wiki

Issue #46 has to be fixed before merging