Fix notification on model change.

AllTimeEntriesView global model change listener failed to notify
about changes to the underlying data, thus breaking databinding.
Fix databinding crash.

BaseModelsViewAdapter was not listening to changes for IsLoading
property, but uses it to adjust the count of the items displayed, thus
if it changed Android threw an exception.
Fix infinite load more.

AllTimeEntriesView had missed setting the HasMore property to true, thus
the infinite scroll (calling LoadMore) didn't work as expected.