Timezone information in HTTP

Hello there,

  Following a suggestion from Julian Reschke I'm sending the attached proposed 
I-D here for discussion. I'd like to know whether you believe that this is 
usefull.

  I'd also appreciate some hints about the timezone format. Julian suggested 
that the format should be changed to the one described in RFC3339 (+OFFSET).  
My original though was that it could be usefull to have the full timezone 
specification as described in POSIX, which includes DST information too. I 
now believe that this should be changed to RFC3339 format in favour of 
simplicity just like Julian suggested.