Add new code examples

[sylvainhalle]

Other examples will come

• Reformulate the primality example of JUnit-Quickcheck: https://pholser.github.io/junit-quickcheck/site/0.8.2/usage/shrinking.html The goal is this: in the Examples project, add a new program that does the same thing as the shrinking mechanism described there, but using Synthia objects.

This is more an "exercise to solve" than a "task to execute", so I omit some details on purpose. A few hints:

• Create a descendant of PickIfSmaller object. The implementation of abstract method select should correspond to the primality check.
• Create a main method that instantiates this object, call pick a few times on it and prints the values it returns.