Bug 160: Replace ICoordinate with IAtomPositioned (extends IAtom), replace ICoordinateKinetic with IAtomKinetic.  Move IAtomPositioned and IAtomKinetic to etomica.atom from etomica.space.  Don't reference AtomLeaf except to instantiate an AtomLeaf.  Clean up casting.
Bug 160: Replace ICoordinate with IAtomPositioned (extends IAtom), replace ICoordinateKinetic with IAtomKinetic.  Move IAtomPositioned and IAtomKinetic to etomica.atom from etomica.space.  Don't reference AtomLeaf except to instantiate an AtomLeaf.  Clean up casting.

ajschult/etomica,ajschult/etomica,ajschult/etomica,etomica/etomica,etomica/etomica,etomica/etomica