Add API that can be used by ember, angular and react frontends

[etewiah]

A useful function of an open source property listings website is to act as a standard API against which to experiment with various JavaScript frontend frameworks.
To this end I am opening this issue to track the development of an API to expose property details as JSON objects that can be easily used by an ember, angular or reactjs frontend.

I have also started on this adaption of an example angular2 / ionic2 real estate app to use the PropertyWebBuilder API:

https://github.com/etewiah/dreamhouse-mobile-ionic