landing page & chat list
move ui changes on static html to backend
Added facebook login and sock_serv use async communicate with django rest api
Merge branch 'master' into front

Conflicts:
	dj_backend/api/serializers.py
	dj_backend/api/urls.py
	dj_backend/api/views.py
	dj_backend/global_statics/css/application.css
	dj_backend/pair_session/views.py
	dj_backend/sock_serv.py