[OpenImageIO/f16] (4 commits) ...Merge branch 'master' into f16

[Richard Shaw]

Summary of changes:

  2a7b94c... Rebuild for new libpng. (*)
  1a39c4a... Update to 0.10.3 Rebuild for libpng 1.5. Fixed bulding agai (*)
  2051691... Update to 0.10.3 Rebuild for libpng 1.5. (*)
  089621f... Merge branch 'master' into f16

(*) This commit already existed in another branch; no separate mail sent