Update serialization to generate proper JSON response for API endpoints
Update dependencies specified in requirements.txt via pip
Add hbattle.core.models to admin site
Refactor Django REST framework API

Update API to include only two (2) endpoints: 'api-battle-list' for a
list of all Battles and 'api-battle' for details of the Battle with
the given id.  If the GET URL query string also includes the parameter
'include_related' and is set to either zero (0) or one (1), that
indicated whether related data should also be included in the returned
JSON.  In the case of Battles, the related data is the list of Players
competing in each Battle and is added to the JSON as the value of the
key 'players'.  If the parameter is NOT present or the value is
invalid, the default is False.
Add custom AngularJS directive for hbScoreboardDisplay

Add basic passing data between Django and AngularJS through the config
script block right after the body of a given template, such as the URL
for the API endpoint to be used.

Use new api-battle endpoint, specifying to include related fields
(i.e., list of Players for this Battle) and now display initial
scoreboard with keywords and scores (all initialized to zero for now).