[memoization] fix incorrect credentials asynchronous loop

[dodikk]

Based on #10

Fixed an issue for the case when wrong credentials are entered by the user.
My memoization fix #9 has caused it.

The issue has been fixed for both the existing UIWebView based demo and for the WKWebView one.

Issue description

The page would not end up loading since wrong credentials will constantly be provided to the authentication challenge callback. For this reason, the credentials alert would not show up (since the credentials have been memoized but they are wrong).

The fix

1. Fixed the condition for supplying the memoized credentials

-(BOOL)isUserInputCredentialsMemoized {
    
    BOOL hasInput = (nil != self.userInput);
    BOOL result = hasInput && self.isUserInputAcceptedByServer;
    
    return result;
}

2. Marking credentials as "valid" in webViewDidFinishLoad:
   If not marked, the alert will show up all over again until cancelled by the user (as it had before).

[hborders]

Same issue as before. I don't think we should mention JAHPAuthenticatingHTTPProtocolDelegate in this implementation because it isn't needed. I think it'll only confuse people.

[hborders]

Ok. This looks good. Are you ready to merge?

[hborders]

It seems like this is a combination of the other two PRs, so maybe you should close them?

[dodikk]

It seems like this is a combination of the other two PRs, so maybe you should close them?

Indeed, it has a few commits on top of those previous ones as I've mentioned in the description. They will be automatically closed by github when this one gets merged.
I'll close them manually anyway as long as you've requested that.