Will override email, display name and avatar URL with the values
provided in 'context.user' structure of the JWT token.

Settings will no longer be used to retrieve local display name,
email and avatar URL. Now those values will be obtained from
the /features/base/participants Redux state.

fix(jwt/middleware): use const for default name

fix: wrong default display name on web

ref(base/participants): remove getDisplayName functions

ref(jwt): do not accept unknown user fields

Prepare for React 16.

Because timeUtil.js computes hours, minutes, and seconds out of a single
time/duration using three separate functions, I wouldn't recommend using
it, especially reusing it. That's why I'm even making the functions
private to their current use location.