ignore-list patch and updated multi-list patch

[Eric Seppanen]

I have a working version of my ignore-list patch.  This patch allows the 
user to specify a list of words that should not be used as spam or ham 
indicators.  It does this by opening a third list file "ignorelist.db" 
(and fails silently if it doesn't exist).

Back when everything was in plain text files, this was a little easier to 
do.  This time, to allow the code to treat all list files the same, I 
decided to try this: you create a plaintext list of words, then call a new 
bogofilter function "-c" that converts the plaintext file to a db file.  
So to create an ignore list, create a file "ignorelist" with all the words 
you want, then run "bogofilter -c ignorelist" and it will create 
ignorelist.db.  Then the next time you run bogofilter, it will ignore 
the words you specified.

An alternative approach would be to create direct support for plaintext 
word lists.  This didn't seem worth the effort just to get ignore lists, 
but if anyone can think of other reasons to support plaintext, I'm willing 
to try the other approach.

As I've mentioned before, this patch requires my multi-list patch be 
applied first.  While writing this patch, I found a few small errors in 
the multi-list patch so I'm publishing a new version of that one too.

Since I have four patches (multi and ignore, for both 0.7 and 0.7.3), I've 
placed them here:

http://www.reric.net/bogofilter/

The 0.7 patches require the getopt patch from a while back, otherwise my 
ignore patch won't apply cleanly.

Eric