BndLib/BndLib_AddSurface.cxx : algorithm of building bounding box for BSpline surfaces is improved
Test cases are modified according to current state of algorithm
Test case bug31995 added
1. Check whether the mesh satisfies the required angular deflection has been amended. Namely normals (to the surface) in the ends of any not "frontier" link are made collinear (with the given angular tolerance).
2. New parameters AngleInterior and DeflectionInterior have been added in IMeshTools_Parameters structure.
3. In case of thin long faces with internal edges, add points of internal edges to control parameters using grabParamsOfInternalEdges() in order to avoid aberrations on its ends. Disable addition of parameters from boundary edges in case of BSpline surface. Deviation can be controlled through the deflection parameter.
4. Grab parameters from edges in case if there is just a single interval on BSpline surface along U and V direction.
