Implemented properly typed graph object.

src/editor/js/graph.js

src/editor/js/structures/graph/graph.ts

src/editor/js/structures/graph/graphelement.ts

src/editor/js/structures/graph/link.ts

src/editor/js/structures/graph/node.ts

src/editor/js/structures/graph/nodetype.ts

src/editor/js/structures/helper/serializableitem.ts

src/editor/js/structures/helper/serializedurl.ts

src/editor/js/structures/manageddata.ts

src/editor/js/structures/space.ts