This commit adds:
- an abstract class for rois and a class bezierPolygonRoi
- a medRoiManagementToolBox which lists all the rois for a given view
- a medHistogramToolBox which contains a view to show histogram
- bezierCurveToolBox can now compute the statistics of a given ROI, it
 does not take care of the visualization of the bezierRoi anymore, this is
 now taken care in the bezierPolygonRoi
 - ...