* 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.

Add more UI states (e.g. differentiating between no access, permission granted but video not loaded, video loaded). CSS cleanup.

Move runtime/renderer related code back into the vm io device. Refactor ModalVideoManager to use the video provider.

Prevent crashes resulting from the editing target not being on the target list.

Separate video provider and modal video manager. Provide hooks in modal video manager for calling functions during stages in enableVideo.

Firefox and Safari both process mp3s as having audio/mpeg, and a variety of different audio/wav* possibilities.

* WIP tips

* WIP first card stack

* WIP use tips reducer to show things to try

* single card deck similar to mask sequence

* collapse option

* Add zoom card

* WIP tips

* Reorganized to redux

* Add zooming to the gifs

* Blue cards + navigation

* Add tips to new nav bar

* Remove blue

* Update design with icons

* deck updates wip

* Updated card decks

* Add videos to libraries

* Update initial card and clicker preview

* Add backdrop to initial card step.

* WIP use vimeo player instead

* New simple spin deck

* Spin around and say hello decks

* Update button and sub-card styles

* Fix "tips" button in menu bar

* Use move cursor

* Fix cursor

* Use same image for deck preview and library

* Fix cursor again

* Update clicker game deck

* Add videos as single-step decks

* Change tips in menu bar to ? icon

* Change “tips” to “how-tos” in library

* Add help icon to cards

* Update deck library images

* Add drag cover for youtube video to prevent catching mouseup

* add a step to spin deck for clicking control

* Blue bar style updates

* Add step pips

* Update clicker game name to run away

* Fix image padding

* Add change color step to spin deck

* Add start sound step to run away deck

* Update say deck to start with adding a sprite

* Remove package lock

* Remove zooming functionality

* Remove unnecassary prototype changes

* Split up rendering of cards into smaller parts

* Use FormattedMessage for all strings

* Automatic lint fixes

* Almost finished with lint errors!

* Fix more lint errors

* Clean up CSS

* Fix webpack config

Refactor video io device to pull HTML DOM related functionality into gui, and for resuability of video device with camera modal.

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.

Update project-loader to look for project id as prop (i.e. from www), and fall back to hash.

- export image and sounds in dist/static/assets
- rename main export (`scratch-gui.js`, not `index.js`)
- move project-loader-hoc back to lib (VM doesn’t load properly without it)

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

Thanks @ericrosenbaum!