added class TimeTest for testing class Time
fixed microsecond/millisecond issue in class Time
fixed issue in class TimeMock and TimeMockTest
rebuild class TimeMock (still issues in Tests)
added debug prints
changed signature of method operator- and operator-= in class TimeMock
Merge branch 'develop' into evaporation
a few changes to the Time class
added copy constructor for class TimeMock
changed the internal structure of class Time (and related classes)