Sorry for the hassle everyone, I was in a hurry when I sent the patch
(actually, it was 01:45 a.m. and I wanted to go to bed – shouldn't do
that, I know^^).

The main patch is still quite big, but there are a few changes that
make it seem messier than it actually is:
- I have changed the name of mKWinConfig to mNewConfig in order to
better express the purpose
- I have split up the loading code in Options::updateSettings into
subroutines (actually, I have not changed anything except for adding
the backup related code)
- I have renamed the "reinitCompositing" DBus signal to
"reloadCompositingConfig" in order to clarify its purpose
- As I have mentioned before, it took me several iterations to find a
solution. Thus, there are a few basically unneeded changes in the
patch. However, I think they make the code easier to understand, so I
have not removed them.

The second patch contains a small fix (the dropdown boxes for the
window/desktop switching effects were not updated correctly if all
related effects had been disabled) and removes some unused code.

The third patch contains a few comment changes and a lot of whitespace
changes to make the code comply to the KWin coding standards.

I have just created these three with the help of "git add --patch" and
had no time to them yet, so the might not be fully independent.

The patches are attached this time, if you prefer a fancy HTML
rendering, you can still have look at them at
http://github.com/klickverbot/kwin/commits/configbackup.
Please bear with me if I have again made some major mistake ;)