Emit token_expires if token has already expired

[coltonneil]

Current behavior:
A new visitor comes to my site, I configure OAuthService and get an access token. After a certain amount of time decided by my timeoutFactor OAuthService emits 'token_expires'. (as intended)

A visitor comes BACK to my site after some time and their token has already passed the timeoutFactor (but is not yet expired). OAuthService does not emit 'token_expires'.

Suggested solution:
When an access token exists OAuthService checks that tokens expiration against the timeoutFactor as part of it's initialization. If the token has already passed the timeout factor it emits 'token_expires'

Alternative:
Calling hasValidAccessToken() will emit 'token_expires' if the token has already passed the timeoutFactor (hasValidAccessToken still returns true/false based on existing logic)

[jeroenheijmans]

I don't have time right now to search for them, but I'm sure there's other related issues, or even PRs to improve this already.

[manfredsteyer]

should be solved with version 9