Closing Interstitial became background instead foreground

[BoschAlejandro]

When closing an interstital ad from admob the Foreground instance became background instead foreground.

It resolves changing the call onActivityResumed to:
@OverRide
public void onActivityResumed(Activity activity) {
current = activity;
}

Best regards and good job!
Alex.

[steveliles]

Thanks for the bug report :)

There's some unfortunate non-determinism in the current implementation that possibly triggers this problem. An interesting pull-request #3 also arrived today that may resolve your problem, since it completely removes the non-determinism. I don't yet know if it introduces other issues as I haven't had a chance to try it out.