Added new Option to configure yakbak to record only successful requests

[rameshsunkara]

Hello Guys,

We are using Yakbak to facilitate faster responses in our development environment.

Some of you might have faced this situation before : sometimes the backend api may not be fully functional in dev environments and as a result the requests will fail. Once we change the backend api to send correct response, we always have to delete our existing tape because the error was already recorded for that request. (Its an inconvenience to find the exact tape and delete, so we end up deleting entire tapes folder)

So to address that situation, I added this new option which helps configuring yakbak to record responses only for the successful requests.

I hope you will accept this feature and make yakbak more awesome.

Thanks, Ram