Add coverage config.

.coveragerc

+[run]
+omit = notesserver/settings*
+       *wsgi.py

Makefile

-test:
+test: clean
 	./manage.py test --settings=notesserver.settings.test --with-coverage --cover-package=notesserver,notesapi \
-		--exclude-dir=notesserver/settings --cover-inclusive --cover-branches
+		--exclude-dir=notesserver/settings --cover-inclusive --cover-branches \
+		--cover-html --cover-html-dir=coverage/html/ \
+		--cover-xml --cover-xml-file=coverage/coverage.xml
 
 run:
 	./manage.py runserver 0.0.0.0:8042
@@ -8,3 +10,6 @@ run:
 shell:
 	./manage.py shell
 
+clean:
+	coverage erase
+