OnDemandList: make sure async errors propagate to the refresh promise
_StoreMixin: avoid bug with `when` in Dojo 1.8

See http://bugs.dojotoolkit.org/ticket/16667
Pagination: emit dgrid-refresh-complete event like OnDemandList
Make OnDemandList dgrid-refresh-complete event props match Pagination's
Merge pull request #411 from kfranqueiro/store-fixes

Store fixes