Update app to latest remoteStorage.js (test build)

I upgraded to the latest rs.js beta (actually an even newer test build that fixes an annoying bug).

Everything seems to work great so far, with one exception: In Firefox Angular has problems with the promises used in `markCompleted` and `setTimeTracking`, which causes it to multiply the list items in the UI. Doesn't happen in Chrome at all, and as an Angular noob I couldn't find out how to fix in within 45 minutes. Maybe you can find out more about that...