Rather than assuming that the storage instance will be attached to a VM,
just return it. Callers may attach it to a `VM` or (in the case of
`import_sb2.js`) to a `Runtime`.
* Add costume dataURI to costumes from storage
Towards #515, LLK/scratch-gui#279
* Fix tests
* Load costumes incrementally
Some of our tests assume that at least some of our costume data is available before the costume data is loaded. So, provide as much costume data as is available.
* Remove unnecessary filter for null costumes
Resolved when we updated to load costumes incrementally.
/ht @cwillisf
- Attach the storage module to the VM for tests which load projects or
other assets.
- Move `import_sb2.js` from `test/unit/ into `test/integration` since it
now depends heavily on `scratch-storage`.
- Skip loading costumes when there is no renderer.
