Error summary at the end of each test & campaign 

Last commit is relevant (https://github.com/jakub-g/attester/commit/1eae95857ffbadb9a3eb2b28dbf8f53288dc6b2c), based on other branches (#40)

I'm counting errors and failures on the slave, perhaps this should be done in `json-report` instead? But this seemed a bit strange for me, it would require augmenting the `event` on-the-fly when it arrives to the `json-report` before it is dispatched to `console-report`. I checked and it works but seems hacky to me.

I've also refactored some three-liners into one-liners, like this:

        if (!info) {
            info = {};
        }
->

        info = info || {}; 
 I don't like unnecessary explicit branches, it makes code harder to read, especially when there are lots of ifs like that in the function.

---

Here's the preview of updated logging (the first error is actually an issue with Attester itself after recent refactoring):

![preview](https://f.cloud.github.com/assets/1437027/901133/a2163b50-fb77-11e2-9c58-9be4da2c2e8d.png)

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