(bug 43124) add toggle for wikibase edits in watchlist

this is not the ideal solution, but the core watchlist code needs
a bit of polish and improved hook points in order to implement a nicer solution,
and we still need null revisions for the watchlist query to work better.

- includes qunit and selenium tests

patchset 12: run client qunit tests automatically

Change-Id: I62d961bcae8a3b601350551827868591217b02d2