update testArithDSS3d according to CForwardSegmentComputer
Merge branch 'Arith3Dtristan' into ArithmeticalDSS3d

Conflicts:
	tests/geometry/curves/representation/testArithDSS3d.cpp
Corrections to enable confounded points in ArithmeticalDSS
FrechetShortcut: files creation + beginning of implementation
Inclusion and modification of backpath and cone classes
working on FrechetShortcut: compilation ok
Compilation ok, basic test ok
test segmentation + example -> patch needed in GreedySegmentation
ajout getSelf
minor edit
resolve conflict
Revert "minor edit"

This reverts commit f487112919a5e7d71f4226865cf92af80ea02426.
Revert "test segmentation + example -> patch needed in GreedySegmentation"

This reverts commit e8e5985739c4a78456a38f65861de9d7b8217521.

Conflicts:

	src/DGtal/geometry/curves/representation/FrechetShortcut.h
GreedySegmentation simple test + example ok
frechet shortcut drawable with board -> does not compile yet
first test FrechetShortcut display
Backporting ConvexIntegerPolygon (wip).
Add board visualization to ConvexIntegerPolygon.
test and example with board display
Add half-spaces to ConvexIntegerPolygon.