Refresh token support

A refresh manager added.
This manager will automatically refresh an access token 10 minutes
befroe it expires.

The refresh token will also be used to try to recover
after 401 return code or if a user opens web-client with an expired
access token and still valid refresh token.

Change-Id: I8ce8f8800a36785cf761c1dbb486c58686a25498
Merge "Refresh token support"