Created on 22 Jan 2013
Base class from which different call back classes can be derived. Callback is responsible for storing the results of the runs.
method for retrieving the results. Called after all experiments have been completed
default callback system callback can be used in performExperiments as a means for specifying the way in which the results should be handled. If no callback is specified, this default implementation is used. This one can be overwritten or replaced with a callback of your own design. For example if you prefer to store the result in a database or write them to a text file