develop (#43)

* fix(ts): use strict mode strictNullChecks etc

* chore: Use extended React.HTMLAttributes<> (#41)

* refactor(code-format): add prettier closes #42

* feat(renderer): add snap to grid option closes #20

* chore(dependabot): use develop as target branch

dist/index.d.ts

@@ -0,0 +1,5 @@
+import ReactFlow from './container/ReactFlow';
+export default ReactFlow;
+export { default as Handle } from './components/Handle';
+export { MiniMap, Controls } from './plugins';
+export { isNode, isEdge, removeElements, addEdge, getOutgoers, } from './utils/graph';