Fill buffer of itk image to zero in ImageContainerByITKImage.ih

[phcerdan]

PR Description

When creating an ImageContainerByITKImage using the domain constructor, fill to zero the itk image buffer.

Discovered using:

    using Domain = Z3i::Domain ;
    using Image = ImageContainerByITKImage<Domain, unsigned char> ;
    unsigned int foreground_value = 255;
    auto thin_image = ImageFromSet<Image>::create(thin_set, foreground_value);
    typedef itk::ImageFileWriter<Image::ITKImage> ITKImageWriter;
    typename ITKImageWriter::Pointer writer = ITKImageWriter::New();
    writer->SetFileName("my_image.nrrd");
    writer->SetInput(thin_image.getITKImagePointer());
    writer->Update();

ImageFromSet::create uses the domain constructor, and the image isn't initialized to zero in the case of ImageContainerByITKImage.

Checklist

• [NA] Unit-test of your feature with Catch.
• [NA] Doxygen documentation of the code completed (classes, methods, types, members...)
• [NA] Documentation module page added or updated.
• New entry in the ChangeLog.md added.
• No warning raised in Debug cmake mode (otherwise, Travis C.I. will fail).
• All continuous integration tests pass (Travis & appveyor)

[dcoeurjo]

Thanks. Merging this PR.