Handle GPS week rollover in GPSDate.

src/main/java/org/orekit/frames/EOPHistory.java

src/main/java/org/orekit/time/GPSDate.java

src/site/xdoc/changes.xml

src/test/java/org/orekit/Utils.java

src/test/java/org/orekit/time/GPSDateTest.java