Done. 
RE: check ClientID. But this is already being verified in [CurrentBearerTokenScope method](https://github.com/crhym3/go-endpoints/blob/ea8f8980a135ced95643b3ed0f4bb73ece13a236/endpoints/auth.go#L472) which calls `tokeninfoContext.CurrentOAuthClientID`:

```go
func CurrentBearerTokenUser(c Context, scopes []string, clientIDs []string) (*user.User, error) {
	scope, err := CurrentBearerTokenScope(c, scopes, clientIDs)
	if err != nil {
		return nil, err
	}

	return c.CurrentOAuthUser(scope)
}

func CurrentBearerTokenScope(c Context, scopes []string, clientIDs []string) (string, error) {
	for _, scope := range scopes {
		clientID, err := c.CurrentOAuthClientID(scope)
		if err != nil {
			continue
		}

		for _, id := range clientIDs {
			if id == clientID {
				return scope, nil
			}
		}
		// If none of the client IDs matches, return nil
		return "", errors.New("Mismatched Client ID")
	}
	return "", errors.New("No valid scope")
}
```

unless I'm missing something, which actually could be considering how much stuff I missed in the prev. commits :(