Fix corrupt DS output for older MSVC compilers
Fix corrupt DS output for older MSVC compilers

The recent removal of strtod() added a bug in the handling of the
non-standard three-digit exponents that old MSVC compilers used.
The bug is now fixed after adjustment of the streambuf.

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