various #include fixes: since proto.h includes nano.h, only include the
former in source files; also add an #include guard to proto.h, and make
the config.h #include in nano.h match the config.h #includes everywhere
else


git-svn-id: svn://svn.savannah.gnu.org/nano/trunk/nano@2471 35c25a1d-7b9e-4130-9fde-d3aeb78583b8
14 files changed