Add script to execute all examples

[tritemio]

@boutellerc, I think we should add a script to execute all the MATLAB script you provide in a single step.

This is useful both as an example itself and for testing. When we release a new version of phconvert we need a simple way to run all the examples to make sure we didn't break anything. When tests are easy to run they are run more frequently, detecting bugs sooner (so they are easier to fix).

For example in phforge, I have a simple function (run_tests()) which runs the script for each measurement type.

Similarly, phconvert has a notebook to automatically execute all the other notebooks included with phconvert in a single step.