Use store.js to overcome issues with localStorage / JSON compatibility on 2.3.x
Merge pull request #38 from SpiderOak/use-store.js

Use store.js to overcome issues with localStorage / JSON compatibility
Convert storage to use .urlBase files/folders scheme.  Simpler, and get any
concern for accountManager (eg, storageRootUrl) out of FoldersView.js.
Merge branch 'convert-storage-to-urlBase' of github.com:SpiderOak/SpiderOakMobileClient into convert-storage-to-urlBase
Encapsulate composition of collection + model url, including provision for
urlBase, in a new Model method, .composedUrl().  This new method
additionally provides for url and urlBase that are methods.