Better overlap rules #779

We now have the concept that either an entire route is overlap checked
or not. This is essentially what we had before, except there was code
littered everywhere on the mistaken assumption that just one component
could be overlap checked. This also allows us to mark parent routes or
multipiece components as non-overlapped checked.

In addition, if you put a bang at the beginning of the pattern, the
entire route is not overlap checked. The previous syntax is kept for
backwards compatibility.