Scale space tool

Two tools to display curvature behavior at different scales, like for instance command:
./estimators/curvatureScaleSpaceBCC -f ${DGtal}/examples/samples/contourS.fc --gridStepInit 0.001 --gridStepIncrement  0.0005 --gridStepFinal 0.05 -o cssResu.png
will produce this result:
![cssresubcc](https://cloud.githubusercontent.com/assets/772865/2646108/f515b0a2-bf39-11e3-96f8-c7606173f43b.png)