1.2.1

Particular thanks to Yaroslav Halchecko for fixes and cleanups in this
release.

• Bugfix release
• Make compatible with pydicom 0.9.7
• Refactor, rename nifti diagnostic script to nib-nifti-dx
• Fix a bug causing an error when analyzing affines for orientation, when the
  affine contained all 0 columns
• Add missing dicomfs script to installation list and rename to
  nib-dicomfs