Fixed: build error with ImageMagick 6.8.8

files and reference works

rmagick.h
* QuantumDepth -> MAGICKCORE_QUANTUM_DEPTH
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#a50dcb9a593bf913ae89919b276efbaee

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rmenum.c
* LABColorspace -> LabColorspace
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#ad75aed188cdae36d08968344ce64d84d

---

rmilist.c
* AverageImages -> EvaluateImages
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L829">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

* MapImages -> RemapImages
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L4355">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

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rmimage.c
* MapImage -> RemapImage
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L4298">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

* MedianFilterImage -> StatisticImage
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L4731">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

* RecolorImage -> ColorMatrixImage
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L5943">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

* ReduceNoiseImage -> StatisticImage
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.c#L5994">ImageMagick/deprecate.c at master · trevor/ImageMagick</a>

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rminfo.c
* QuantumDepth -> MAGICKCORE_QUANTUM_DEPTH
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#a50dcb9a593bf913ae89919b276efbaee

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rmmain.c
* QuantumDepth -> MAGICKCORE_QUANTUM_DEPTH
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#a50dcb9a593bf913ae89919b276efbaee

* MaxRGB removed (MaxRGB -> QuantumRange)
<a href="https://github.com/trevor/ImageMagick/blob/master/branches/ImageMagick-6.8.8/magick/deprecate.h#L59">ImageMagick/deprecate.h at master · trevor/ImageMagick</a>

* LABColorspace -> LabColorspace
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#ad75aed188cdae36d08968344ce64d84d

---

rmpixel.c
* QuantumDepth -> MAGICKCORE_QUANTUM_DEPTH
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#a50dcb9a593bf913ae89919b276efbaee

---

rmstruct.c
* QuantumDepth -> MAGICKCORE_QUANTUM_DEPTH
http://www.sourcecodebrowser.com/imagemagick/6.4.5.4.dfsg1/magick_2deprecate_8h.html#a50dcb9a593bf913ae89919b276efbaee

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### reason for version 6.4.5.4 sources

>  s.requirements << 'ImageMagick 6.4.9 or later'

<cite>[rmagick/rmagick.gemspec at master · gemhome/rmagick](https://github.com/gemhome/rmagick/blob/master/rmagick.gemspec#L22)</cite>

6.4.5.4 < 6.4.9
Therefore, I didn't use "#if defined", "#endif".