I guess QuantumDepth is now MAGICKCORE_QUANTUM_DEPTH
ColorspaceType LABColorspace is now LabColorspace
- Replaced GetExceptionInfo everywhere / changing exception to *exception
- count up gem version
- Replace deprecated functions like http://www.imagemagick.org/api/deprecate.php describes
  -> AverageImages
  -> DestroyConstitute (removed, I guess it's not necessary to do this anymore)
  -> MapImage
  -> MapImages
  -> MedianFilterImage (seems to be removed, so I did)
  -> RadialBlurImage[Channel] (seems to be removed, so I did)
  -> RecolorImage (seems to be removed, so I did)
  -> ReduceNoiseImage (seems to be removed, so I did)

Might now compile properly with newer ImageMagick!