Relax the file meta-header check slightly
Relax the file meta-header check slightly

Previously, we required the DICM magic number had to be followed
by 0002,0000 (the meta-header group length tag). However, some
files don't have it (although the standard requires it). To allow
loading of these files, we now allow the DICM to be followed by
any tag (0002,0010) or below.

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