Removed MLS object from datomic.  MLS is now a superset of the place object.
* Test to get the expanded mls entity.
* Find mls entity by its mls-id.
Routes return valid JSON.  Need to turn URIs into strings.
* MLS object gets returned when an mls-id is provided. Issue #4
* MLS-id is expected to be string, not a number.
MLS is now a superset of place-objects.
* Uses same input functions.
* Tests pass.

 is necessary,
# especially if it merges an updated upstream into a topic branch.
#
# Lines starting with '#' will be ignored, and an empty message aborts
# the commit.