nrrd.field.key: Parse a NRRD header field name into a lookup key.
Description
NRRD field names are matched case-insensitively and some fields are spelled in two
ways ('line skip' and 'lineskip', 'data file' and 'datafile'), so a key is computed by
lowercasing the name and dropping everything that is not a letter or a digit.
Usage
nrrd.field.key(name)
Value
character string, the normalized key.
Arguments
name
character string, the field name as it occurs in the file.