Merge pull request #21 from atlasapi/broadcast-deserialization

Set URI on Broadcast Channels when deserializing Broadcasts
Add AtlasWriteClient interface for writiing people to an Atlas

Add interface for writing with a writePerson method, implemented by
GsonAtlasClient.
Merge branch 'mbst-6741-post-people' into stage

* mbst-6741-post-people:
  Add AtlasWriteClient interface for writiing people to an Atlas