[hypermail] large checkin - new options

 I have checked in a fairly large set of changes that I described in: http://www.hypermail.org/hypermail/mail-archive/1999/Sep/0064.html http://www.hypermail.org/hypermail/mail-archive/1999/Sep/0042.html  They shouldn't affect anyone who doesn't use the new configure options.  This is mostly merging features I added in critmail several years ago, and the code mostly got extensive testing there.

 I have also checked in a script tests/diff_hypermail.pl to compare archives (which I used to test whether the changes I made affect the output under common configurations).

 Short summary of the new options:
showhtml: new option value 2 gives richer conversion to html borrowed   from txt2html.pl.
monthly_index: create additional index files broken up by month. yearly_index: create additional index files broken up by year. thread_file_depth: break the threads index file into multiple files,   roughly one per thread.
linkquotes: creates fine-grained links from quoted text to the text   where the quote originated. It also improves the threads index file   by more accurately matching messages with replies. searchbackmsgnum: with linkquotes and -u, speeds up processing, with   some risk that linkquotes won't find all links it should. link_to_replies: generate links from original quoted text to the   location(s) in replies which quote them. quote_hide_threshold: If the linkquotes option is on, replaces quoted   text with links in messages which quote too much. quote_link_string: with quote_hide_threshold, use this text in place   of first line of quoted text.

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Peter McCluskey          | Fed up with democracy's problems? Examine Futarchy:
http://www.rahul.net/pcm | http://hanson.gmu.edu/futarchy.pdf or .ps