fix json.net dependency issue
fix json.net dependency issue

wallymathieu/FsPickler,FsUnity/Unity3d.FsPickler,cloudRoutine/Unity3d.FsPickler,nessos/FsPickler,FsUnity/Unity3d.FsPickler,cloudRoutine/Unity3d.FsPickler,wallymathieu/FsPickler,nessos/FsPickler,haraldsteinlechner/FsPickler,haraldsteinlechner/FsPickler,mbraceproject/FsPickler