More intelligent return value tracking.

[devill]

Right now we track the method calls and if the method name matches we return the logged return value. In most cases this works, but in some failure cases - for example when there is a new void call introduced that or an old one removed it would be better to try and find a best match. This is more a nice to have feature, and might create more headaches then it solves, so it should be low priority and it should be discussed before implementation.