The main class "Speclib" has been changed in that the additional information
is now stored in the SI slot (function "SI" replaced "attribute" for
update/access). This change was used to restructure how the supplementary data
is internally stored and allows the user to use e.g. raster images as source
of additional information (which can be of advantage if e.g. terrain is
suspected to play a role for hyperspectral classification/regression).
Additionally, the Speclib-class has now methods compatible with the
iteratively reading/writing functions of the raster-package (writeStart-,
writeValues-, writeStop-methods for Speclib class are implemented).
Besides these technical changes, the new version of PROSPECT (version D) is