sci-libs/itk-4.4.2-r1: fork from itk-4.4.2.ebuild
sci-libs/itk-4.4.2-r1: Add vtkglue use flag

Enable Module_ITKVtkGlue if vtkglue use flag is set. VtkGlue is used for
glueing an ITK pipeline and a VTK pipeline together.
sci-libs/itk-4.4.2-r1: Move examples to /usr/share/${PN}

The sibling ebuilds of sci-libs/vtk put examples into
/usr/share/vtk/examples/. Use the according destination for ITK too.
sci-libs/itk-4.4.2-r1: Add doc use flag

Install doxygen documentation tarball if doc use flag is given.