feat(users): implement checking username existence for new users

close #145
feat(auth): implement ally-py server authentication
refactor(auth): use authAdapter within auth service
test(auth): make e2e tests pass with animated modal
fix(auth): add fade animation to login modal
refactor(build): add server:test task for e2e testing
refactor(auth): store user info into local storage
fix(auth): fix ci issues
chore(tests): add code coverage report for unit tests
test(auth): remove storage handling from spec, use service api
test(travis): make test coverage report visible on travis
feat(auth): new login screen

Add HTML and CSS for login page

Add "loading" state info

lint errors fix

Add changes for login error
test(travis): set reporters via karma conf
feat(auth): integrate new login screen
feat(tests): send code coverage to coveralls