Random fixes to hippotat

[Ian Jackson]

Mark Wooding writes ("Random fixes to hippotat"):
> I now have this installed and running.  I had to fix it; my fixes are in
>         https://git.distorted.org.uk/~mdw/hippotat/
> in the branch
>         mdw/fixes      e13eca8e1facf849a7825b815adc72ef142b7ca8
> 
> I've done some archaeology on the spurious-`Content-Length' bug, and I
> can't see any reason why anything written even slightly recently would
> try to set `Content-Length' explicitly.

Oh.  Well.  I guess it's a mystery.  Thanks for investigating.

Merged to master, thanks.

Ian.