GroupStrengthWeightFactory (probable) bug fix

* Fixes a (probable) comparision error in GroupStrengthWeightFactory
* Adds equals and hashCode to Group
* Adds GroupTest, checking equals, hashCode and toString
(cherry picked from commit 760ef05)
Added logger, fixed a NPE in GroupStrengthWeightFactory
Added TeacherTest and equals/hashCode to Teacher
Added a Person super-class to both Student and Teacher
Added SeminarTest, fixed up Person and PersonTest
Added unused methods to SeminarTest
Added some tests to SeminarAppTest

* Changed access from private to protected of prepareDataDirStructure()
Renamed Groups*Test to Seminar*Test
Added SeminarHelloWorldTest
Adds SeminarGeneratorTest
Adds SeminarImporterTest
Adds SeminarExporterTest
Ignored SwingUI test
Added mockito and mocked out SeminarDao in SeminarGeneratorTest
Added SeminarBenchmarkTest and fixed benchmark configs
Updated SeminarApp dataDir creation and fixed up SeminarAppTest
Minor tweaks in SeminarHelloWorldTest and SeminarExporterTest
Updated plugin version in pom
Updated SeminarApp and SeminarAppTest
Adds test of SeminarInputBuilder exceptional cases to SeminarImporterTest