reorganising classes and adding Builder implementation
fully recursive algorithm
refactoring and adding comments
refactoring
Merge branch 'master' into merging

Conflicts:
	src/main/java/fjab/worldcup/CombinatorialImpl.java
	src/main/java/fjab/worldcup/MatrixUtil.java
	src/test/java/fjab/worldcup/MatrixUtilTest.java