Cover art support for Google Drive

[sigdrak]

Before posting

Please follow the steps below and check the boxes with [x] once you did the step.

• [X] I checked the issue tracker for similar issues: #6201
• [X] I checked the changelog if the issue is already resolved
• [X] I tried the latest Clementine build from here

System information

Please provide information about your system and the version of Clementine used.

• Operating System: Windows 64bits
• Clementine version: 1.3.1/1.3.2RC1

Expected behaviour / actual behaviour

Expected: Clementine loads the cover art from either the file (in this case m4a) or the folder (Front.jpg/Back.jpg available, and appropriate filenames set in Music Library) Actual: only title/artist/Album/length seems to be present, cover data from folder and file are ignored

Steps to reproduce the problem (only for bugs)

Add a Google Drive provider and let it finish scanning

[JulianVolodia]

@sigdrak as I said in #6426 maybe you could send patch and we could work together? Have you some time?