Graph Prop: isInteractive (#56)

* feat(props): add isInteractive

* refactor(selection): dont allow if not interactive

* feat(renderer): add class if is interactive

* chore(inactive): add tests

* refactor(inactive): no connection line, no edge selection

closes #49

dist/components/UserSelection/index.d.ts

@@ -1,3 +1,3 @@
 import React from 'react';
-declare const _default: React.MemoExoticComponent<() => JSX.Element>;
+declare const _default: React.MemoExoticComponent<() => JSX.Element | null>;
 export default _default;