Remove $Id$ keyword expansion
This commit removes all Id
keywords in the Xenofarm source code. Now
that we are using Git, they don't do anything useful.
Opera have more contributions pending, but the pointless diffs due to
differnt keyword expansion in our Git tree and the upstream Git tree
makes it needlessly hard to see exactly what we have to contribute.
So as a first step I'd like to get rid of all Id
keywords.