breaking exn handling out of rhpl & anaconda

[Chris Lumens <clumens redhat com>]

I've spent the last few days trying to break the exception handling out
of both rhpl and anaconda, combining them into their own project.  The
benefits for this are obvious:  helping to get rid of rhpl, and letting
tons of other programs make use of save-to-bugzilla.

Anyway, my current work in progress is here:

   http://clumens.fedorapeople.org/exn/

Making this generic enough is a little annoying but I think I've managed
it.  The UI is probably the most complicated part.  My reasoning for
doing it like you see is so we can still support text and graphical
interfaces, and so that anaconda can provide its own wacky UI classes
that override what I've done.  That's why the abstract interfaces look
awful familiar.

test.py is obviously not a part of this module, but it does show how to
use the thing from a programmer's point of view.  This is likely to get
a little more complicated when I work on bugzilla support but that's
just the nature of working with bugzilla.

Things still left to do:

- test save to bugzilla - it should "compile", but probably doesn't do
  anything
- work up a patch for anaconda, rhpl, firstboot, system-config-*, etc.
- do all the typical project stuff (translations, spec file, etc.)
- add wait dialogs as well - there's a bug about this somewhere
- write docs describing how to make this easier to use
- make sure everything's robust
- your pet requirement here

Any questions?

- Chris