reducing # of cherrypy threads in debug mode

@jamalex suggested this could have been a cause for recent memory problems on the central server.  Can be adjusted in local_settings if desired.

Why 5?  No good reason at all.  Could have been 1, but seems unnecessary to go that low.

It is my contention that doing a pull request on this is a waste of time.  As is feedback.  If 5 is such an offensive number that it warrants discussion, a better approach is to merge, then do a new pull request.

I will not assign, because this is an issue for anybody to consider.  I will happily merge this tonight, if it is not done by then.