[imp] filterprefs.php and the template system

[Liam Hoekenga]

We'd created a couple of locally used preferences to toggle the display 
of the blacklist / whitelist links (show_bw_lists), and the spam 
reporting links (show_spam_links), and traditionally they've been 
located in on the filter's preference screen.

I figured out what I need to do to to add them to imp/filterprefs.php, 
and they show up.. but since they begin with show_ instead of filter_,  
templates/filter/prefs.html won't save them...

<loop:opts>
<input type="checkbox" id="filter_<tag:opts.key />" 
name="filter_<tag:opts.key />" <if:opts.checked>checked="checked" 
</if:opts.checked>/> &nbsp;<tag:opts.label/> &nbsp;<tag:opts.help/><br />
</loop:opts>

I could put in a second "input type" line, with show_, but then it 
displays everything twice.  Not really what I want.

What would I add to get it to process both filter_ and show_ ?  Short of 
renaming my prefs

Liam