PunchCardAnalyzer

Added PunchCardAnalyzer interface.
JUnit

Added Junit to lib folder
GregorianTimePeriod

Added GregorianTimePeriod to system. Beginnnig TDD implementation.
Finished GregorianTimePeriod

Finished TDD implementation of GrgeorianTimePeriod. No documentation
yet.
GrgeorianTimePeriod documentation

Added JavaDoc to GregorianTimePeriod.