* Make error overlay to run in the context of the iframe

* Configure webpack to build the entire package

* Remove inline raw-loader config

* Configure watch mode for error-overlay webpack build

* Add polyfills to the error-overlay iframe script

* Add header comment

* Configure to fail CI on error or warning

* Suppress flow-type error on importing iframe-bundle

* Change webpack to a dev dependency and pin some versions

* Disable webpack cache

* Update license headers to MIT

* File headers BSD+Patents -> MIT

* BSD+Patents -> MIT

tagging dev-only code (@remove-on-publish-begin/end) and pre-eject-only code (@remove-on-eject-begin/end) #257 (#257)