various changes to cut down on binary size: per DB's patch, add new N_()

various changes to cut down on binary size: per DB's patch, add new N_()
macro to mark strings that aren't translated immediately and convert
nano to use it where needed, overhaul the shortcut list and toggle list
initialization code for efficiency, and replace rcfile_msg() with
rcfile_error(); also add a few minor miscellaneous cleanups by DB and
myself

git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@1852 35c25a1d-7b9e-4130-9fde-d3aeb78583b8