HTML::Template does not read files as utf-8, so modifying ikiwiki's
template files to contain utf-8 won't currently work.

It seems that the best way to fix this would be to make HTML::Template
support utf-8.

A workaround is to change all the template reading code like this:

	-     my $template=HTML::Template->new(blind_cache => 1,
	-             filename => "$config{templatedir}/page.tmpl");
	+     open(TMPL, "<:utf8", "$config{templatedir}/page.tmpl");
	+     my $template=HTML::Template->new(filehandle => *TMPL);
	+     close(TMPL);

However, this will make ikiwiki slower when rebuilding a wiki, since it
won't cache templates.