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

src/files.c

@@ -35,7 +35,6 @@
 #include <pwd.h>
 #include <assert.h>
 #include "proto.h"
-#include "nano.h"
 
 static file_format fmt = NIX_FILE;
 	/* The format of the current file. */