koji wsgi support

[Mike McLean]

I just pushed a large commit adding wsgi support to koji-hub and 
koji-web. This feature had been on the back burner for a while, but the 
recent retirement of mod_python in Fedora has forced the issue.

Here's the summary I wrote for the (squashed) commit:
Support wsgi in koji-hub and koji-web
  - mod_python still supported, but deprecated
  - mod_wsgi is the default
  - koji-web now configured via web.conf
  - new wsgi-friendly publisher for koji-web
  - koji-web now has logging

This is a fairly large change. I've gone out of my way to maintain 
compatibility with mod_python, but migration issues are still possible.

Ideally, though, folks will move to mod_wsgi. This will mainly be a 
matter of adjusting httpd.conf files and moving koji-web config from 
http conf to the new web.conf file. I'll write a longer doc on this 
later, but for now:
- see the comments in the example http.conf files for hub and web
- see the example web.conf
- generally the web.conf options have the same name as the old koji-web 
PythonOptions

I'm not quite ready to cut a release with this yet, but soon. There 
needs to be more testing.

If you opt to try out the new code, please report bugs in our trac:
https://fedorahosted.org/koji/report