Upgrade to JSGI 0.3

[kriszyp]

This covers the pull request for upgrading to JSGI 0.3 when we are ready.
http://github.com/kriszyp/jack/

[gmosx]

yes, yes, yes ;-)

[kriszyp]

Just FYI, I never finished upgrading everything in Jack to JSGI 0.3, I did the servlet and simple handler, and several middleware packages. I know Dean Landolt and Nick Fitzgerald had talked about doing the rest, but AFAIK it has not been completed. Most of what is left should be straight forward.