[[ Bug 13208 ]] Reimplement OSX colorspace handling and add support for PNG cHRM chunk
[[ Bug 13208 ]] Add Win32 support for calibrated RGB colorspace
[[ Bug 13208 ]] Ignore image alpha when transforming colors on OSX
Merge remote-tracking branch 'ian/bugfix-13208' into bugfix-13208
Merge branch 'bugfix-13208' into develop