Fix swapped upper and lower bounds on ConcreteCalendarInterval.

Because the upper and lower bounds are swapped, the new test fails on line 42 with the following error:

testTranslationToTimeIntervalFromCalendarInterval(com.domainlanguage.time.CalendarIntervalTest)  Time elapsed: 0.004 sec  <<< ERROR!
java.lang.IllegalArgumentException: com.domainlanguage.intervals.IntervalLimit@b2eddc0 is not before or equal to com.domainlanguage.intervals.IntervalLimit@31e06dfc
        at com.domainlanguage.intervals.Interval.assertLowerIsLessThanOrEqualUpper(Interval.java:301)
        at com.domainlanguage.intervals.Interval.<init>(Interval.java:43)
        at com.domainlanguage.intervals.Interval.<init>(Interval.java:49)
        at com.domainlanguage.time.TimeInterval.<init>(TimeInterval.java:64)
        at com.domainlanguage.time.TimeInterval.over(TimeInterval.java:19)
        at com.domainlanguage.time.TimeInterval.over(TimeInterval.java:24)
        at com.domainlanguage.time.ConcreteCalendarInterval.asTimeInterval(ConcreteCalendarInterval.java:27)
        at com.domainlanguage.time.CalendarIntervalTest.testTranslationToTimeIntervalFromCalendarInterval(CalendarIntervalTest.java:42)