Release 0.3.15

From NEWS:

• !120 (merged) Detect libsoup version from grl-net and adds support to libsoup3

• !123 (merged) youtube: port to API v3 by using libgdata 0.17.0

• !122 (merged) tmdb: port to GUri, remove libsoup dependency

• !122 (merged) dleyna: port to GUri, remove libsoup dependency

• New translations

  • Abkhazian
  • Dutch
  • Galician
  • Georgian

• Updated translations

  • Abkhazian
  • Basque
  • Bulgarian
  • Danish
  • Hebrew
  • Nepali
  • Occitan