refactor(localforage): create a constructor for the localforage object
feat(localforage): add support for multiple storage instances
test(localforage): add tests fot multiple storage instances support
fix(test.api): fix PhantomJS - SECURITY_ERR on multiple instances tests
fix(localforage): fix localStorage fallback, when webSQL driver fails
Merge pull request #253 from thgreasi/instances2

feat(localforage): add support for multiple storage instances
Use error-first callbacks (close #219)
Use `err` not `error` for consistency's sake