Moving Bathymetry Operator into common session(extension-vtk)
This MR moves Bathymetry Operator from discrete to model session which mainly purpose is to expose BO to polygon session.
So now instead of getting data from vtkPolyData in discrete session, now we directly get the data from tessellation. Meanwhile, We use a vector to store zValues as FLoatProperty to realize remove bathymetry functionality. Two test cases are added for discrete session(.cmb and .2md file).
Addresses issue #94 (closed) .