When trying to insert the raw content of an attached shell script
called `whatever` using:

    \[[!inline pages="whatever" raw="yes"]]

The generated HTML contains:

    \[[!inline Erreur: Can't call method "param" on an undefined value
    at /usr/local/share/perl/5.10.0/IkiWiki/Plugin/inline.pm
    line 346.]]

Looking at the inline plugin's code, it is clear that `$template` is
undef in such a situation. Defining `$template` just before line 346,
in case it's not defined, removes the error message, but nothing
gets inlined as `get_inline_content` returns the empty string in
this situation.

If we explicitely don't want to allow raw inlining of unknown page
types, ikiwiki should output a better error message.

> I have made it just do a direct include if the page type is not known, in
> raw mode. That seems useful if you want to include some other file right
> into a page. You could probably even wrap it in a format directive.
> 
> It does allow including binary files right into a page, but nothing is
> stopping you pasting binary data right into the edit form either, so
> while annoying I don't think that will be a security problem. --[[Joey]] 
