0.15.0

Changes since 0.14.0:

• Update LibRaw from 0.19.5 to 0.20.0
• Update libjpeg from 9c to 9d (#112)
• Update libjasper from 2.0.16 to 2.0.19 (#116)
• Expose white level metadata (#102)
• Fix opening files with non-ascii filenames on Windows (#85)