Script to automatically test the tool

I have created some scripts to automatically test the tool and have stored them in the new folder called: 'tests'.

The script: 'test_examples.py', which receives a folder and an output file, run the tool over all tests contained in the given folder (and subfolders), collects a summary of the result and writes it in the output file.

The script: 'analyze_results.py' receives the output of the first script and checks if the obtained results match the expected ones (which now are included at the beginning of each example as a comment) and show the results of this comparation.

There is a file called 'results_29_10.txt' which contains the output of an execution of 'test_examples.py'. Some examples are too slow so I stoped them by keyboard interrupt. This is why the analyzer returns 'At least one of the tests was too slow' for some cases.

An example of use could be:
./test_examples.py ../examples output_file
./analyze_results.py output_file

In https://github.com/smackers/smack/blob/master/bin/smackverify.py#L131 I don't see they use this ' shell = True' option. Why is this needed?