Questions:
* should the message strings include the number? Or should that get added to the name when the name is defined
* added a new ‘shared-messages’ to handle the definition of backdrop, costume, etc which are used in multiple places, they’re all related to defaults, so should it all be in `lib/default-project`

styling for title field; correct input target in tests; make download filename safer with default, max length; in playground index, correctly pass props through to gui container

/ht @chrisgarrity

Removing this was the point of moving the test up one level. Thanks @chrisgarrity, good catch!

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

Just use ProjectLoaderHOC to translate props to redux. Trying to be clever about using both props and redux state together was... not clever.

Resolves #3040