Fix thread race conditions when automatically registering components with Castle Windsor

Hi Seb,

I'm hoping this is a fix for the race conditions mentioned in [this thread](http://groups.google.com/group/openrasta/browse_thread/thread/6ac8f36beab63ab6?pli=1) on the OR mailing list. We've also seen the issue crop up when registering codecs.

I'd be interested to hear your thoughts on whether there would be any problems registering this way?