operation: setup NetCDF support.
mapping: plane by 3 points.
modified:   ../distortion/CImg.mapping.cpp: add 3 points on command line.
modified:   ../distortion/mapping.h: add 3 points support.
modified:   ../operation/CImg.operation.cpp
warping: setup dev version and image processing step show.
modified:   CImg.mapping.cpp: small change (WiP).
modified:   CImg.warping.cpp: add option for showing image processing steps (e.g. blurred and binary images).
modified:   Makefile: setup development version for warping.
modified:   VERSION_WARPING: version v0.0.7.dev .
warping: setup version for light slope removal.
modified:   CImg.warping.cpp: setup light slope removal (see -s option).
modified:   Makefile: setup v0.0.8 version.
modified:   VERSION_WARPING: v0.0.8 version .