Extract FamilyTree as a class and specific test to modules

The relationships between family members make more sense in their own class, separated from the genetic test itself.
Also, the particularities of each test should be independent from the test class itself. By being in a module, you can plug and play with different test without modifying the basic operations of a genetic test.
Extract example into its own file to be run away from lib files.

I overlooked the fact that the running of the example was inside the genetic testing class. I have isolated the running example in its own file away from the library itself.
Merge branch 'cleanup'