Bump the version number to 0.4.3.
Bump the version number to 0.4.3.

This version provides some build fixes for building against the vtk
packages installed on debian systems, and for building with MSVC.

dgobbi/vtk-dicom,hendradarwin/vtk-dicom,dgobbi/vtk-dicom,hendradarwin/vtk-dicom,hendradarwin/vtk-dicom,dgobbi/vtk-dicom