Fixed a typo that broke automatic youtube video support in `addurl`.

----

Now there's an easy way to get an overview of how close your repository
is to meeting the configured numcopies settings (or when it exceeds them).

<pre>
# time git annex status . 
[...]
numcopies stats: 
	numcopies +0: 6686
	numcopies +1: 3793
	numcopies +3: 3156
	numcopies +2: 2743
	numcopies -1: 1242
	numcopies -4: 1098
	numcopies -3: 1009
	numcopies +4: 372
</pre>

This does make `git annex status` slow when run on a large directory tree,
so --fast disables that.