Merge branch 'stat' into 'master'

src/account/__init__.py

src/account/admin.py

src/account/apps.py

src/account/migrations/0001_initial.py

src/account/migrations/0002_auto_20171114_2144.py

src/account/migrations/__init__.py

src/account/models.py

src/account/serializers.py

src/account/tests.py

src/account/urls.py

src/account/views.py

src/kszkepzes/settings.py

src/kszkepzes/urls.py

src/stats/__init__.py

src/stats/admin.py

src/stats/apps.py

src/stats/migrations/0001_initial.py

src/stats/migrations/0002_auto_20171111_1646.py

src/stats/migrations/0003_auto_20171114_2026.py

src/stats/migrations/0004_remove_kszkevent_num_of_pers.py