Deprecated day of year computation in DTM2000 model.

DTM2000 atmosphere class uses Java class GregorianCalendar in method getDensity to compute the day of year.

No TimeZone is provided so that the default TimeZone is used. Default TimeZone depends on user's machine so it can be different than "GMT+00".

Day of year computation should not be dependent on user's default time zone. Method DateComponents.getDayOfYear should be used instead (as in NRLMSIS00.getDensity).