warping: bug correction of threshold value compution.
modified:   CImg.warping.cpp: ad min value to threshold.
modified:   Makefile: upgrade to developpemement version.
modified:   VERSION_WARPING: v0.0.7.dev .
add cross threshold on command line.
modified:   CImg.warping.cpp: add cross threshold as command line option.
warping: add blur.
modified:   CImg.warping.cpp: add image bluring before thresholding cross (static value to 2).
warping: add blur coefficient on command line for smoothing before thresholding.
modified:   CImg.warping.cpp: add blur as command line option.