GARANT COMMANDS: load spin system library - loads library defining possible fragments

usage: load spin system library <read(.lib)>

The specified library <read(.lib)> is loaded. It contains lines such as
   GLN GLU MET GLU-
which indicates that the four fragments GLN, GLU, MET and GLU- are of the same spin system
type. This information is used in the automatic assignment routines to exchange the 
assignments of these fragments.

This command has to be used prior to any other commands. As soon as an other command is 
used the default library is read.