GUI includes its own Intl provider (react-intl supports nested intl providers) that works within the www intl provider.

Restore the app-state provider intl provider and app-stat-hoc for the stand-alone gui so that IE can function enough to put up the unsupported browser.

This is taking advantage of the fact that react-intl can support nested IntlProviders. GUI will use it’s own ConnectedIntlProvider, that maintains the translations in redux, while www will continue to have it’s own IntlProvider that is initialized when the page loads.

Moving the IntlProvider into GUI meant that nothing in the playground can use injectIntl, so the default project name needed to move into the component instead of being in the reducer.

The Localization HOC is added, it takes an optional onSetLanguage handler, so www can pass a function that will set the cookie that www needs.

/ht @chrisgarrity

If the VM is ever instantiated, which happens whenever GUI is instantiated due to default props, then IE11 will crash

Locale detection function that checks browser setting and lets URL parameter (locale= or lang=) override the browser setting.

* updated locales reducer to include current messages and messagesByLocale (the previous all messages)
* moved locales out of gui
* include locales in the things exported by gui (index.js)

Add `?locale=<localecode>` to load in a new langage.
Add `?enable=language` to enable the language selector
Or combine the two: `?enable=language&locale=<localecode>`
Still accepts a hash, but requires that the hash be a sequence of digits.

Added new locales reducer to gui:
- initializes default  react-intl/localeData
- initializes default locale messages for all locales
- default locale is ‘en’ (can be overridden by URL)

Removed dependency on react-intl-redux, added ConnectedIntlProvider (uses correct locale messages from redux based on current locale)

Move guiMiddleware to `reducers/gui.js`, and use it in `app-state-hoc`

* Export initial states for each reducer
* combine all gui reducers (excludes scratchPaint and intl)
* combine all initial states to create default guiState for preloading in www
* expect all of the gui state to be accessible at `state.scratchGui`

GUI will export a reducer to be included in the enclosing component’s redux when GUI is used as a library. The app-state-hoc is moved into the playground examples to provide a store when GUI is being used stand-alone.

Also extract the "supportedBrowser" logic into a helper (rule of 3)

* Player mode

Add isPlayerOnly property on GUI. Move isFullScreen into mode reducer with isPlayerOnly.

Full screen needs to be a separate prop so that GUI knows what to show when exiting full-screen (either player-only or full editor).

- set `gui-body * {box-sizing: border-box;}` instead of expecting it to be set by the enclosing component/playground, and removed uses of content-box (adjusting sizes as needed) 
- Added `!isPlayerOnly` to the conditions for draggable sprites
- rewrote player example to use player mode.

The initial intl store expected an object with an `intl` key, not the intl object as returned by `injectIntl`.

Also changed GUI proptypes to accept Object as well as String for projectData to avoid warnings.

Allow intl to be passed in to GUI as a prop (rather than having to be already in the store)

Add Error Boundary (has componentDidCatch method) to handle WebGL errors and display an informative message.