Check for current user in RecentTimeEntriesView.

When adding new models from OnModelChanged message, the user of the
changed time entry was not checked against the currently logged in user.
Fix time entry continuing.

The newly created time entry was not persisted and was not associated
with the user of the previous time entry.
Implement automatic duration updating.

Running time entries duration is now updated auto-magically. Whenever a
model that is running is in memory, it starts the update looping, which
runs until all of the running models have been GCed.
Mark model as shared after adding to the cache.

Now that the IsShared property is set to true after the model has been
added to the cache, the event handlers can be sure that the model that
just became shared is present in the cache as well.
Remove useless delay when no running time entries.

When there were no running time entries the EnsureLiveDuration would
still wait 500ms, during which time there could've been added some new
running time entries, but were in fact ignored due to that delay.
Add INTERNET permission to manifest.