ENH: Initial implementation of the PolyData converter.
ENH: Export PolyData through OpenIGTLink. Attributes are not exported.
ENH: Export attributes. All features for the POLYDATA converter are implemented.
ENH: Simplify vtkIGTLToMRMLPolyData::MRMLToIGTL() using vtkIGTLToMRMLPolyData::VTKToIGTLCellArray() function.
ENH: Simplify vtkIGTLToMRMLPolyData::MRMLToIGTL() using vtkIGTLToMRMLPolyData::VTKToIGTLAttribute() function.
ENH: Clean up the code.
STYLE: Remove debug code.
Merge pull request #45 from tokjun/3907-POLYDATA-support

3907 polydata support