config template: documentation updates

Make the template a little clearer. SSH commands are for connecting to
remote hosts, not the remote hosts+path combination going by $REMOTE in the
main script.

Bitpocket is handy for syncing music players and flash sticks, so hint at
some good flags to use with FAT filesystems.
sh: permit REMOTE_PATHs with spaces

Allow $REMOTE_PATH to contain spaces (hosts too, I guess).

Make an error message quote $REMOTE too, for a little more clarity when
there are spaces in the path.
init: permit an empty hostname

Allow init to be passed an empty hostname argument. The config file allows
it already, referring to local file access for the remote end.

Update usage instructions accordingly.