Add react-error-overlay package (#2111)

* ༼ つ ◕_◕ ༽つ stack-frame-overlay

* Fix linting

* Remove auto overlay

* Fix e2e

* Pull in the rest

* Appease flow

* Correct dep

* Remove old repo references

* Check flow on test

* Test overlay in e2e

* Add cross env

* Rename package

* Make sure it gets built post-install

* Update the README

* Remove extra builds now that there's a postinstall script

* Revert "Remove extra builds now that there's a postinstall script"

This reverts commit 8bf601dbd36c1e0da7f785fa9ade70ab08ed8772.

* Remove broken script

* Fix some dev ergo

packages/react-error-overlay/src/utils/isInternalFile.js

@@ -0,0 +1,10 @@
+/* @flow */
+function isInternalFile(url: string, sourceFileName: string | null | void) {
+  return url.indexOf('/~/') !== -1 ||
+    url.indexOf('/node_modules/') !== -1 ||
+    url.trim().indexOf(' ') !== -1 ||
+    sourceFileName == null ||
+    sourceFileName.length === 0;
+}
+
+export { isInternalFile };