Use "C" locale for DICOM string conversions.
Use "C" locale for DICOM string conversions.

The strtod() method uses "," in place of "." for some locales. This
patch uses C++ streams imbued with the "classic" locale in order to
ensure that the string conversions are compatible with DICOM.

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