The documentation has been updated to reinforce the fact that NDF identifiers obtained
using IMG_INDF are not released by any IMG calls (you must do this for yourself using
NDF_ANNUL).
A new routine for copying sources of header information (HDR_COPY) has been added.
A bug in the FITS header writer that added NULL characters after the END card has been corrected. This should have only affected output FITS headers that contained some initially empty cards.