Versioned config for Elementary.

Versioned config for Elementary.

This is not doing much now, just the version field in the struct,
some stuff stolen from E and a base to use when new things are added.
There are some comments in the code about what to do in certain cases
that E does not have, like a system update, new config and apps linked
to the old version still running when the config Atoms are updated. These
things we'll probably be addressed as they are needed, as well as come
clean up in quick code I ditched in there, but it would be good to do so
with more feedback from the good guys around that like to break SVN
every now and then.

Since the commit message is already long enough, I'm adding some more crap
just for the sake of doing so. I could go with some tl;dr thing as well,
but I don't feel like resuming what's up there.

Have a nice day.

SVN revision: 51843