Visu markers

visu ok mais generation image pas encore
ex: ./DGtalBranchVisu.app/Contents/MacOS/DGtalBranchVisu -i  ../output.sdp -c 246 270 30  
![capture decran 2013-06-11 a 23 55 29](https://f.cloud.github.com/assets/772865/639943/ec973616-d2e1-11e2-954e-fd38f975a512.png)