Version 1.6.0

R interface

• The niftiHeader() function gains an "unused" argument. If TRUE, the
  function's return value includes those legacy ANALYZE-7.5 fields that are
  formally unused by the NIfTI-1 standard (or the last few bytes of a NIfTI-2
  header). These fields cannot be set, however, as the niftilib I/O functions
  discard them, and the core nifti_image structure does not represent them.
  They also cannot be accessed with the $ operator shorthand. The option is
  therefore only useful to inspect file headers created by other software.

API changes

• The NiftiImage class now has constructors taking a NIfTI header structure.

Other changes

• The NiftiImageData::Iterator inner class now holds a pointer, not a
  reference, to its parent. This doesn't really change the API, but ensures
  that iterator objects are mutable, which is formally required by the C++
  standard. (Prompted by Timothy Anderson, issue #31.)
• There is now support for standalone use on Windows with the Visual C++
  toolchain, including an nmake-compatible makefile, and this is now tested
  as part of package CI. The package also no longer includes symlinks, for
  better portability. (Prompted by Timothy Anderson, issue #31.)
• The bundled zlib is now version 1.3. The included zlib headers are no
  longer exposed to client packages if the system zlib is used for linkage,
  as the two may be incompatible.