[PATCH] callout part selector tweak

Martin Schwenke <martin@meltin.net> asked for this feature and posted a
patch:

 The following patch almost let's me have the following configuration:

  PROGRAM="/sbin/aliaser %b %k %n %M %m", RESULT="?*", NAME="%c{1}", SYMLINK="%c{2+}"

 allowing me to specify an arbitrary number of symlinks by saying
 "giveme the second and later words"."

Here is the actual version with tests and a few words in the man page.