#20 add Mockito to project
(cherry picked from commit b5d75b86a8bf29144658e9040007a4d586b2a972)

Conflicts:
	pom.xml
#20 replace custom mock verification with mockito
(cherry picked from commit 817e7091d5ac39bd5c5d301e771e0baab1789c90)

Conflicts:
	src/test/java/de/frosner/datagenerator/main/DataGeneratorTest.java