Template expansion via _#{...}_ now removes a final newline if such a
final newline is present. (It doesn't remove more than one newline.)

The final newline is really an implementation artifact of files; it's
there because lines end with newlines, not because people consider it
to be part of the file's *real* content. Deleting it thus brings
template expansion closer to inserting people's idea of the file's
contents into place.

It also means that we avoid having templates introduce whitespace into
undesired places. For example:
>  [There's more starting at %{blog::seemore}#{blog/rangemore}]
and _blog/rangemore_ of:
>  or %{range::moreclip}
doesn't introduce a gap between the end of %{range::moreclip}'s output
and the ']' in what the browser displays. (See how we didn't think of
_blog/rangemore_ as *actually* having a newline at the end as part of
it?)