update to support locals

Sanford's engine api now takes locals.  This updates the engine to
honor locals that are passed to it.

This also updates the handling of the passed service handler.  This
is no longer referred to generically as "scope" but instead specifically
as "service handler".

This just makes the engine compatible with the latest Sanford engine
API.
Merge pull request #2 from redding/kr-locals

update to support locals