We recently did a `hg copy` of a directory in our repository. We thought it
does something like `cp -a` and `hg add` and maybe flag somehow that
this file has been copied from another file inside the repo (so `hg
annotate` shows the original committer). But it now seems that `hg
copy` does more or different stuff than that. I couldn't really find
much on how exactly copy works. So:

* What exactly does `hg copy` do and what special treatment does this
cause in the future?
* If it turns out to do "the wrong thing(tm)" for our case, how do I
unflag the file as beeing a copy of another file?

(This question was asked on the Mercurial mailinglist, you may want to [follow the original thread](http://mercurial.markmail.org/thread/yotjumnywxes5q4j) too.)