Implement Result to encapsulate expected results and tests results

[gpestana]

Implement a Result type which encapsulates expected results and tests results.

The Result type must keep information about number of alerts triggered and its type (ok, warn, crit). An instance of Result can be constructed with data from the test configuration file or from the node-stats entry of the kapacitor task.

The method compare is implemented to compare two results. This method will compare an expected result with a test result. If the Results are the same, the test pass. Otherwise it will fail.

The String method of Test will compare the results and print whether the test has passed or not (and show the reason why it didn't)