added Christine and FX as contributors
added Christine and FX as contributors

attatrol/Orekit,treeform/orekit,CS-SI/Orekit,Yakushima/Orekit,CS-SI/Orekit,attatrol/Orekit,liscju/Orekit,liscju/Orekit,ProjectPersephone/Orekit,petrushy/Orekit,ProjectPersephone/Orekit,petrushy/Orekit,wardev/orekit,Yakushima/Orekit